Be warned, this will be long and very detailed.
For background, I'm currently driving a '09 335i coupe, which I do love, but now that I'm able to afford a little more car, I've got the bug again. I'd also like something with 4 doors to make the change really worth it too.
So I spent the entire weekend test driving a few M3s and S4s back to back to back to get as much experience as I can. I'm going to give an account of both, but keep in mind these are my opinions, and I'm not implying that they are necessarily correct. Don't be offended if I've said something in contradiction to the way you feel.
First, the M3 sedan:
Interior: Quality of materials is top notch, everything laid out perfectly, despite the somewhat "austere" appearance. Part of this could be that I'm accustomed to my 335i, and it's essentially identical in form and function. What few minor differences that existed were generally positive (like the added bluetooth functionality on 2011.5 models, the center armrest extender, and other bits). The one thing I didn't care for was the soft touch plastic trim around the shifter. I actually like the aluminum in my 335i better, and it found me wishing that that piece had received the same trim as the dash, since over time the plain black plastic will probably show wear quickly. Seats couldn't be more comfortable. Grip you and swaddle you at the same time. Just incredible. Back seat was comfortable too, just enough room without being too big. My biggest gripe is that they don't have Coral Red for the interior. I thought I wanted Fox Red until I saw it in person. Now I don't care for it. It's more like brick, really. Too much brown for my tastes. I'm not sure what that leaves me with. I guess black, but that seems so mundane. Hate silver, and I've never seen Bamboo. It seemed that the coupe seats actually felt better than the sedan, but I guess that doesn't make sense, since they're the same exact seats, right? I don't like the fact that they essentially
make you purchase the hi-fi sound system for a whopping $2k now, since the base system just sucks..bad. Wish they had a L7 system for $800ish like the 3er.
Exterior: What's not to like. It's an M3. A perfect 10 imo. It's got that mean, aggressive look (especially the comp package that I'd plan on ordering) that I love.
Handling: Wow, just wow. It was hard for me to get a good idea of what aspect of the M Drive was really making the difference (power, EDC, steering), but when you set that car up for spirited driving, it just feels like heaven going through the twisties. Oddly enough, the coupe I drove seemed to feel better than the sedan, though they weren't back to back, so its hard for me to assert that the difference is real. Anyone have input on the comparison between coupe and sedan?
Transmission (M-DCT): Incredible. _Insert other superlative_. The only fault I could find with the system was that it didn't like to downshift in D mode. Even in D-5, downshifts required substantial throttle application to occur. This is not at all the case with my 335i. I'm sure this is to pump up the EPA figures...sadly. I don't know that there's anything I can do about it either, unfortunately.
Engine: The sound is pure bliss. I could literally listen to it all day long. Unfortunately, the power plant doesn't exactly scratch me where I itch. After driving my 335i, the power delivery of the M3 just isn't immediate enough for me. I know it's actually fast, it just doesn't _feel_ fast until I get it at least 4-5k rpm. The power and torque are definitely there, I just had to work a lot harder to find them than in the 335i. Luckily the M-DCT makes the job much easier. I know many have said it, but the lack of torque in the lower rpm band (below 3k rpm) is really a detractor for me. When this is coupled with the transmission's resistance to downshifting unless you really goose it (in D mode), this definitely makes the car feel a little less than the supercar than it is. I definitely feel like I could learn to drive this car in such a way that it would feel really fast all the time (i.e. keep revs up much more than I do now), but it would probably result in terrible gas mileage. Then again, it'd be an aural delight.
Overall: The package was great, I truly loved it. Handling was extremely crisp and controllable, the engine sound was ecstasy, and the interior was comfortable and solid. However, if I'm honest, the lack of torque did dampen the experience for me. I was also put off by the fact that I couldn't stand Fox Red (which leaves me limited interior color options), and the _perceived_ difference between the sedan and the coupe. For whatever reason, the coupe just _felt_ better. I'd love it if someone came in here and (honestly) told me I was nuts, and that they both should feel virtually identical while driving.
Now the S4 (this will have some comments referring to the M3 for comparison, since it occurred afterward):
Interior: I used to think Audi was far and away BMW's better in interiors, and there are quite a few things I _do_ like better about the B8 S4 interior than the M3, but it's certainly not so cut and dry. The overall quality of materials in the Audi definitely felt subpar. For example, there is a large piece of silver plastic trim that surrounds the MMI display that looks like it's something that should have been rejected from an Infinity. This piece should match the material in the inlays (aluminum, carbon fiber, etc). Also, little things like the complete lack of armrest pads on the doors in the Audi made it feel a little cheaper and less comfortable. On the other hand, many things about the Audi trounced the BMW, like the seat aesthetics (the black and red nappa leather seats with red contrast stitching for seats and steering wheel was to die for), the info vie w on the gauge cluster is multi-color and conveys much more information, the little dials for volume and selection on the wheel are very ergonomically pleasing, the tach and speedo that sweep from 6 oclock position instead of the standard 7:30 position like a Ferrari, the interior lighting scheme is a nice cool white/red instead of a (imo) garish orange/red, and others. The seats in the Audi were very nice (better than my 335i), but I'd put them just a peg below the M3 in comfort, plus they don't have the adjustable bolsters like the M3 (a trifle, but nonetheless). I didn't like the diminutive second cupholder in the Audi, but I do like that the first one is deep and located in the center console, not on the dash. Still, have to give the edge to BMW for the cupholders. I missed the small storage compartment under the armrest in the S4. I kept trying to "open" the armrest, as it feels thick enough that it should open. Also unusual since I recall my 2000 S4 had an armrest that would open. I did like the fact that it was height adjustable. A major letdown in the S4 was the height of the door armrest. I felt that it was too low to use for anything but the lowest seat height setting. Maybe it's just me. Also, it could use a thicker steering wheel. I liked the MMI system a lot, and the B&O sound system was great (though it could really use an EQ), but I think I'd give the nod to the BMW Nav system/interface. After getting used to using the Idrive system in my '09 335i, it's hard to beat the efficiency you can achieve with the 7-button system on the BMW. The Audi system was nice, but I think even with a lot of use I'd probably have to look down to find most of the buttons that are farther from the knob. The glove compartment in the S4 was nice and spacious, but seemed to hit my knees when I sat in the passenger seat even with the seat moderately far back. The rear of the S4 was very nice, and had little elastic map pockets on the front seatbacks (something conspicuously absent on the M3). I also missed the M3 (and 335i) interior "club" lighting. Maybe I just couldn't see it though as it wasn't fully dark yet - does the S4 have ambient lighting in the door areas like BMW?
Exterior: The S4 is one classy car. It's the best looking S4 to date, by FAR. This certainly says a lot. However, aside from the cool LED daytime running lights, it just doesn't have the "mean" factor that the M3 has. It looks more proportionate as a sedan than the M3 does though, I think. I like the aluminum mirrors and the rear of the S4 definitely looks better than the M3. From some of the other angles though, it appears a little plain compared to the M3. I would have liked some fender flares over the somewhat slab sided A4, but I guess they reserve those for the RS-series only. Just a few more cues to the fact that you're getting more than an A4 with the S-line package would be nice. The wheels were the biggest weakness IMO. The standard split 5-spoke on the prestige package are a little ho-hum, and the Ti "sweep" 5-spokes if you get the $400 Ti Sports package looked dreadful in photos (though I admit they might be better in person).
Handling: The S4 I drove did not have Audi Drive Select or even the sport differential, so this may change if those are added, but I really felt that the S4 handled extremely well. Actually, much better than I thought it was going to. It did resist rotation a little when I really pushed it, but it took a lot to get to that point. It felt so planted and surefooted that it was extremely confidence-inspiring in the twisties I took. Didn't feel quite as _good_ as the M3 dynamically, but felt like it would handle a short spirited drive with just as little drama and just as much fun as the M3. On the track, I'm confident the S4 would do very well, though it might not feel as good as the M3 while doing so. The ride in the S4 was perhaps a touch more rough (again, without ADS) than the M3 in comfort or normal settings, and maybe on par with the M3's sport EDC setting.
Transmission: Loved the S-tronic about as much as the M-DCT. It felt a little closer to a true automatic since I didn't get the slight feeling of a slipping clutch at low speeds like the M3, but it felt superb when up/downshifting while moving along. Shifts were clean and extremely quick, just like the DCT in the M3. Auto mode left something to be desired, as it was also saddled with a logic that demanded short shifts at 1500 rpm (I'm told you can adjust this if you use the dynamic setting with ADS, but again, this car didn't have it). Just like the M3, you really needed to get into it in order to wake the car up. Also like the M3, the auto mode was smooth as butter on accel and decel. A major gripe of mine with the S4 was the "farting" noise that accompanies upshifts under heavy throttle. I'm told this is normal and is a byproduct of extreme rev reduction by the ECU to rev match for the next gear. It doesn't sound _that_ bad, but I'm sure I'll have to answer questions about it any number of times when I carry passengers. Unfortunately it gets louder with an aftermarket exhaust too (which the S4 could really use). Another gripe I had was that the S4 doesn't indicate which gear it's in when in Auto mode, making downshifts for passing something of a best guess.
Engine: Ohh, lord. Man, did Ingolstadt do this one right. _If_ I have anything bad to say about this engine, it's that it isn't loud enough. Sadly, I'm not sure I could ever put an aftermarket exhaust on for fear of louder "farts". The engine in the S4 is just fantastic. Pulls HARD at all points of the tach; there is _always_ power when you want it. Until I drove this, I actually thought my 335i had very little lag. In truth, I still do, for a turbo, but this is truly lag-less. The only other nit is that the power band seems to flatten after about 6k rpm, which effectively reduces your redline even further. Still, with the flat torque curve on the S4, that's at least 4500 _very_ useable rpms. I've read that some tuners are opening up that power from 6k up too, so there may be more to the story eventually.
Overall: The S4 does about 95% of what I want it to do extremely well. It feels fast (much faster than I expected), it handles well, it feels very planted and secure, it has a great interior with few faults and a phenomenal aesthetic, it has a very smart looking exterior, and it can do everything I could conceivably want it to do with aplomb. Unfortunately it didn't give me the emotional connection I got with the M3. I never felt like I was driving a $60k sports car, I felt like I was driving a very fast and sporty looking luxury car.
The decision: Unfortunately, after some real reflection and a lot of test driving, I'm still not sure which car I'm going to go for. I really hate to admit it, but I'm actually somewhat biased toward the BMW since I've been a BMW guy for the last 6 years and they've always treated me right. The last Audi I owned I loved to death (2000 S4 2.7 T), but it did leave me with a big repair bill on account of failed turbos, and I always felt like the ugly duckling when I would show up to the DC metro area BMW car club meets with my S4 (they met far more regularly than the Audi group at the time). I know that the S4 has come a LONG way since then, and I shouldn't let this affect my decision, but if I'm honest to myself, it does a little. Despite everyone saying that the S4 is a competitor to the 335i, and the M3 is more competition to the RS4, I disagree. It may be that an M3 could spank an S4 at the track, but in my experience, both handle much better than my 335i, and both have similar features and benefits for a _roughly_ similar cost. My brain is telling me to just forget the M3 since the daily drivability (read: torque) of the S4 beats the M3 pretty substantially. And I probably spend 70% of my miles commuting, so that's a strong selling point for the Audi. Plus it has AWD and an interior aesthetic that I'm going to appreciate more than the M3 on a day to day basis. However, at the end of the day, I'm not getting into an M3, and the emotional attachment of the M3 just won't allow me to move on and forget it. Right now I'm about 60/40 in favor of the S4, but I can't seem to truly make up my mind. Oh well, I suppose I could have worse things to worry about.
Any thoughts?
I think you deserve some kind of award if you read all of this, btw.