I was talking with Uber V8 in his E92 vs E90 thread (which I accidentally co-opted into a “How to rev match” tutorial), and he asked me to compare my GT4 to the E92 M3 6MT I had before, and then I remembered that others when I took delivery had asked me to follow up with impressions after I’d gotten some time with it as well. So now that I’ve got 3200 miles and 3 track days at CotA on it, I figured I’d write up some observations and put them into a new thread rather than burying it somewhere else. For context, I’ve been an HPDE instructor for about 18 months now. On the M3 I had Yoko AD08Rs, camber plates, a StopTech BBK, and better pads and fluid, and on the GT4 I’ve only got fluid and some boring parts necessary to get a better alignment to avoid prematurely destroying tires at the track. I’m also currently DDing my GT4 (my DD needs are fairly minimal), so my comparison covers a wide range of aspects here, and I’d be happy to write up more if anyone asks. I’ve broken this very long post into named sections for people who don’t want to read the whole thing.
Obviously these cars are different animals. Since it’s still early, I haven't gotten as comfortable with the GT4 yet as I was with my M3, although it does inspire a ton of confidence right off the bat rather than intimidating you like a Vette or Viper might, for example. Still, a lot of variables have changed on me all at once: 700 lb weight reduction, mid-engine, aero grip, and sticky Michelin Pilot Sport Cup 2 tires -- and that’s before fiddling with the adjustable aero, coilovers, and sway bars, none of which I'll be touching for a while since I figure I need to learn to drive what I’ve got before I start deciding how to change it. So it's hard to say to what degree each aspect is responsible for the difference in driving impressions, but here goes:
Handling: The GT4 on track is much more tossable than the M3 (mine was non-ZCP, fwiw). That was obvious even the first time I went out for fun on a road with tight corners, but even more so right away on track. Turn-in is fantastic, and I can carry much more speed into corners and through the esses at CotA while still changing direction the way I need to. I chalk this up to mid-engine layout, lower weight, and extra grip all together. I also found myself trail braking the GT4 much deeper into corners since the chassis could handle it, and this actually goes a long way to curing the understeer that some have complained about on the GT4 -- so does getting more than the stock -1.5 camber. Looking back on the M3 now, even having experienced the GT4 I certainly wouldn't describe the M3 as "lumbering" when it comes to cornering, and I was totally happy with it while I had it, but it was definitely slower to change direction. This isn't a big deal on the road, though, since the M3 can still carry more speed through corners than even a skilled driver would probably want to unless they had a death wish, but the GT4's turn-in immediacy and sensation of lightness is still cool and still noticeable even in that setting. And not directly related to handling, but the GT4's stability control is much more permissive than the M3's. I had Euro MDM coded on my M3, which when I used it pretty much stayed out of my way unless I'd messed up, but on the GT4 you need about 50 degrees of yaw before it will step in at all
even while it's fully on. The M3 even with Euro MDM enabled stepped in well before that point. One thing that seems backwards to me about Porsche's GT-specific system though is that you can turn stability control completely off and leave traction control on, or you can turn them both off. But there's no way to turn traction control off to have full throttle control and keep stability control on to handle yaw -- so Porsche is happy to let you spin backwards into a wall, but at least the car was helping you manage wheelspin?? Reading up, this seems to be because the system was originally designed for 911 GT cars, where stability control with a rear engine layout causes the rear brakes to get used up very quickly, so people wanted a way to turn it off. I doubt that problem will exist on a Cayman, but we'll see. Anyhow, I thought having only on/off toggles would be a step backwards from having MDM's "intermediate" mode (which incidentally non-GT Porsches also have), but it's plenty permissive even when fully on.
Braking: The GT4 can generate serious Gs in the braking zone on track compared to my M3 even though it had upgraded tires and PFC 08 pads in a StopTech BBK on the front axle. With that setup I sometimes had to reduce pedal pressure on track to avoid tripping ABS because I had more brake than tire. The GT4's stock Pagid pads are roughly comparable to the PFC 08s, but its Cup 2 tires are grippier than the AD08Rs, the rear tires are larger, and it's much lighter, so I don't have that issue anymore. If I'd had Cup 2s on the M3 it might have closed this gap somewhat, but now we're comparing a fairly modded M3 to a bone stock GT4. Stock for stock though, the GT4 is leaps and bounds ahead of the M3, although I've read that even the GT4 boils its stock fluid at CotA, so I already upgraded that. And I don’t think I’ll have to worry about upgrading any other brake components considering that the GT4 gets the same brakes fitted as standard to the GT3 and RS, which have an extra 100+ hp to slow down and wider tires to grip harder before ABS gives the brakes a break. Maybe slotted rotors with replaceable friction rings purely to reduce running costs and increase rotor longevity, but that would be about it.
Power: This one is actually a draw, because while the GT4’s lower weight more than offsets its horsepower deficit (even with the long-ish gears), the M3 wins on power delivery, for two major reasons. The first is that although the M3 doesn’t start developing real thrust until about 4500 RPM, which is somewhat high in the modern turbo era and why several people erroneously call the engine torqueless, the GT4's engine doesn't deliver its additional kick until about 5500 RPM -- and that's despite the fact that its redline is 600 RPM lower than the M3's. Compounding this issue further is the fact that the GT4's power delivery noticeably drops off short of redline, whereas the M3 pulls hard all the way to top. That compresses the GT4's effective power band even more, down to maybe 1750-2000 revs wide, compared to about 4000 revs on the M3. This isn't to say that the GT4’s engine is disappointing, because it isn’t – it’s just that the S65 in the M3 is an absolute masterpiece. There’s a reason it won International Engine of the Year in its category for the first 5 of the 6 years for which it was eligible, and even in its final year it finished second only to the engine in the MP4-12C. I’m told that in the 991S, which uses the same engine as found in the GT4, the engine has a better midrange and pulls stronger to redline (especially with the Power Kit option) because the 991S's intake plenum and larger throttle bodies allow more air flow. There are aftermarket plenums for the GT4, and the 911 throttle bodies can be added, but then you need a tune and probably exhaust headers to let that extra air in actually get out, and that’s just not worth it to me, especially since I only notice this on track, and even there it’s just noticeable, not bothersome.
Sound (the good kind, not cabin noise, which I’ll address later): Again, I call it a draw. The GT4's sound is of course more immediate thanks to the mid-engine placement (which also makes it louder when you're driving aggressively), and it definitely sounds special in its own right, but the thrill of a high-revving NA V8 is only available from a high-revving NA V8 -- and a truly special thrill it is, channeling muscle car sounds on the low end and F1 cars on the high end. It's the only thing that sort of makes me miss my M3 at the moment, since in basically every other way that matters I like the GT4 more, but on sound the GT4 is just a step sideways relative to the M3. The GT4 at light throttle has a sound that very much resembles gearbox whine but isn't (because it scales with revs even with the clutch in), which creates a sort of futuristic quasi-electric sound down low, but it starts snarling deliciously if you get on the throttle. And just like the M3, from inside the cabin you hear almost entirely intake noise with very little exhaust noise, which doesn’t bother me in either car because both have fantastic intake sounds and I’ve never been a loud exhaust guy anyway. Both the M3 and GT4 exhausts sound fantastic from the outside though, with the GT4's definitely being louder when PSE is enabled. But the S65 for both its aforementioned power delivery and its sound will always have a special place in my heart.
Transmission: I haven’t driven an S2000, but multiple people who have are saying that the GT4’s shifter is as good or better than the S2000, which is the benchmark here. I didn’t really have any complaints about the M3’s shifter (which could be since it was my first manual transmission car), but the GT4’s is otherworldly. The shifter is short, the throws are short, the weight is perfect, and the precision is amazing. No notchy feeling like the M3’s, and gates so well defined I can’t see EVER missing a shift in this car, even shifting under high lateral loads mid-corner on track. The clutch weight is similar to the E9x
non-M cars, i.e. a bit heavier than the M3’s but still absolutely DDable. And even though I expected not to use it, the auto rev match feature is handy on track especially since I’m using 2nd in the GT4 out there, unlike the M3 where I’d usually roll through in 3rd since a 3>2 downshift was tricky in that car and the M3's gearing made it barely worth it at CotA. But I keep that feature disabled on the road since I still enjoy chasing perfectly smooth rev-matched downshifts on my own.
Steering: Similar to the above, I haven’t driven a 991 GT3, but people who have are saying that the GT4’s steering is a bit better than even that car. I’d never know that the GT4 used an electric rack just by driving it. It has more feedback than the M3’s hydraulic rack for sure, which is especially noticeable when loaded up mid-corner on track. The steering weight is similar to the M3 in Normal mode, which I ended up using full-time after using Sport early on during fun/track driving. The steering wheel diameter is noticeably smaller, which seems fitting on a smaller, more agile car, and the thickness of the rim is much less than the M3’s, though in fairness the M3’s wheel is much thicker than most cars. That took a bit of getting used to and for a while it bugged me that the GT4’s wheel didn’t feel as substantial, but I adjusted to that during the break-in and haven’t thought about it again until just now writing this. There are no infotainment controls on the GT4’s wheel, but the only ones I used on the M3 were to change tracks back and forth, and those buttons are on the driver’s side of the stereo and can be operated purely by feel, so I don’t miss those. I have the leather steering wheel btw, mostly because the Alcantara wheel didn’t wow me and I didn’t want to deal with having to either accept a gross wheel after a while or put up with cleaning it constantly.
Ride/seating comfort: Ride quality was a concern for me since I knew I would be DDing at least initially, wouldn’t be able to test drive a GT4 before committing, and would definitely be optioning the carbon fiber bucket seats – but happily it turned out to be a total non-issue. The ride is firm, as a performance car should be, but not at all harsh even though it’s designed for the track. Wonders of a modern suspension, I guess. With PASM in Normal, the ride is basically between the M3’s Normal and Sport EDC modes. In PASM Sport, the ride is noticeably firmer than the M3’s Sport mode, so just as I only used the M3’s Sport EDC mode on smooth tracks (since I had non-ZCP, I had the non-adaptive Sport mode), I only use PASM Sport on smooth tracks like CotA, which incidentally is what Porsche recommends anyway. The GT4’s Nurburgring time was set with it on Normal. As for the bucket seats, they’re absolutely astounding. Not only do they look drop-dead gorgeous, but I actually find them supremely comfortable, even more so than the M3’s seats where I always found myself slouching no matter what I did with the adjustments. I drove 200 miles home in them nonstop after taking delivery and got out without a single ache or pain, and my wife actually took a nap in them! I also found in the recent colder months that the Alcantara centers and wraparound nature of these seats creates a sort of natural seat heating effect for people who can't live without that feature in their cars. Yes, getting out of them takes a bit more effort, but even there I developed a finesse for that fairly quickly, so it’s not a chore for me at all. However, those with physical ailments and/or ladies wearing skirts would definitely have more of a challenge, but I think a bit of work on egress is worth the improved driving experience, because when driving for fun, you just feel that much more connected to the car and in tune with what it's doing. For reference, I’m 5'9", 195 lbs with a 34” waist and find that for me, the backrest width, backrest angle, overall seat recline angle, and seat depth and width are all PERFECTLY judged. I thought the reduced and firmer padding would make the ride harsh, but it didn't at all. It reminds me of when I went from a very cushy office chair to my Herman Miller Embody. Just goes to show that proper design can triumph over extra padding any day. That said, seat feel is definitely subjective. Skinny people have felt these seats aren't worth it since they're too wide to hold them in place, and pretty large people (250+ lb) have felt uncomfortably pinched in them, but most people who have tried them really like them. Some have also found lack of lumbar support to be an issue, but I don’t miss it at all, and there are lumbar cushions for that purpose. One point worth noting is that these seats only offer manual fore/aft and electric height adjustment, no backrest angle or overall tilt angle adjustments. As a result, you do sit pretty upright. I felt right at home since that’s what I had in my M3 given that it’s the proper driving position anyway, but I’ve also sat in the driver’s seat of other people’s cars and noticed how they’re set up for a “gangsta lean” posture. If that’s you, you would definitely have an adjustment period in these. Or of course you can instead get the regular 2-way or 18-way adjustable Sport Seats that you find on other Porsches, but you’d be missing out on some truly special seats.
General DD livability/practicality: I knew I could forego the rear seats, but again since I couldn’t test drive a GT4 beforehand, my main DD-related concerns other than ride comfort were (in no particular order) scraping issues due to the ride height and long overhang, cabin noise, stereo quality, cargo, and the Cup 2 tires – and even here it’s all basically good news. Prior to taking delivery, I started paying closer attention to driveway angles of shopping areas and such where my wife and I went, and there were some that I was sure would be non-starters if I ever had to take the GT4 there. Surprisingly, it hasn’t been a problem. I can take basically everything at an angle to avoid scraping at all (even on heinously steep driveways), and even some road grade changes that I thought would be a problem since an angled approach might not always be feasible I turned out to be able to take straight on. But worst case, the lip is unpainted plastic and is quick to swap, though at this rate I don’t think I’ll have to do that for at least a long while. In terms of cabin noise, it's louder than the M3, but not by enough to stand out for being annoyingly loud, and there's no drone. The stereo is fine, not notably good or notably terrible, just “fine”. Definitely short of the Enhanced Audio on the M3, and the bass is either a bit overblown with Loudness enabled or non-existent with it disabled (and the Bass slider doesn’t help here), but whatever, I hardly used the M3’s stereo anyway since I preferred to listen to the car, and the same is true here. The cargo situation is surprisingly good for this kind of car, mostly due to the rather wide and deep frunk. My friend with an R8 V10 6MT (disappointing car to me, btw) has a much smaller frunk and no rear storage at all, so his car can't really even be used to pick someone up at the airport. However, the fact that the GT4’s total storage is split between two areas means that you can’t take certain kinds of items in either area. For example, I have a watertight storage chest that holds lots of my track gear. It fit perfectly well into M3's trunk, but it’s just slightly too wide for the GT4's frunk, so I have to transport just its contents without the chest itself. Other wide items like framed art don’t really fit in either area very well, but oh well, part of the territory. As for the tires, you’re not supposed to drive on them in temperatures lower than 40 F, and I’m told they can be trouble in heavy rain. Since I can work from home I can probably work around this, but if not I’ll just put PSS on the OEM rims and buy a set of probably 19” track wheels. It’s too early to comment on tire wear rate, but the Cup 2s have a 180 treadwear rating, same as the AD08Rs I was running, and I figure with 8-12 track days per year I’ll probably wear them out on track use rather than road miles anyway, in which case I might not save much cash by getting separate street tires. We’ll see, but I’m hoping to avoid dealing with a second set of wheels, especially since unlike the M3 I can’t transport a full set of wheels in this car.
"In a perfect world" gripes: The aforementioned power delivery could be improved. The gearing could be a bit shorter; 2nd doesn't top out until something like 80 MPH, which is unfortunate given how sublime the shifting experience in this car is. The suspension could have come from the factory with the parts necessary to get a reasonable track alignment. The stereo could sound a bit better, and it would have been nice to have the next-gen PCM head unit that the GT4 just barely missed out on since it has CarPlay, Google Street View, and an overall more modern interface. Porsche Entry & Drive (BMW's Comfort Access) and a rear camera would both have been nice, but neither is available on the GT4. I wish I could have gotten the active headlamps without the stupid headlamp washer nipples (which Porsche ended up getting even more money from me to have painted in body color rather than the regular black....) And lastly, resting one's arms can be tricky. With my seat in the right position, the door sill is slightly higher than ideal for resting my elbow on it while cruising and driving one-handed. But more noticeably than that, the center console armrest is too LOW to comfortably rest my right elbow on, again while driving one-handed. Granted, raising it would have made the interior design look a bit odd, but as a result I find myself resting my right hand either on the shifter or just on my right leg. I noticed early on that something was "off" about the GT4's driving position that had me moving my arms a lot more on, off, and around the steering wheel and hanging onto the shifter while cruising, and I only recently realized that this was why. None of these is a huge deal by any means, though. Like I said, this is just the "in a perfect world" list.
Phew! That ended up being a lot longer than I’d planned, but there you go. Any questions??
EDIT: Just because, pics of the old and new cars:
