Originally Posted by Novator
Hi Taipan168, I actually owned an '09 135i from new and traded it over a year ago for an '04 E46 M3 and honestly couldn't be happier. In the end it depends what you want in a car and how you drive it. When I bought my 135i I was new to BMW and wanted something that was small, relatively quick, easy to mod, and had a warranty. The 135i ticked some really good boxes: It was a 3 liter inline six, twin turbochargers, Under 3,500lb weight, seats 4 people, good gas mileage, and Dinan warrantied performance parts. That was back in August 2008 when I placed an order, when it arrived to me in December BMW had severed ties with Dinan and only select dealerships would continue to sell Dinan products. My dealership in Hawaii discontinued Dinan service unfortunately.
For the most part my 135i remained stock for about a year other than a BMW Performance carbon fiber spoiler and cat back exhaust which included a resonator delete. It wasn't until I returned from Afghanistan I fitted a BMW Performance electronic steering wheel (the price at that time had dropped from $2000 to $1000) and the new BMW Performance Power Kit. I loved the steering wheel and the Performance Power Kit kept me happy for a while, but I still wasn't satisfied. I hated the throttle lag (not to be confused with turbo lag) and wanted more power. Later on I fitted a Sprint Booster and Vishnu V4 piggyback on top of the BMW Performance Power Kit. This worked because anytime I had dealer visits I still had power from the PPK and any ECU codes that came up I would just blame on the PPK flash. The car was an absolute beast power wise with the V4, but now I started to struggle with grip and went from the stock rollers to cheap Kyowa Evolves and Continental Extreme Contact DWs to lighter APEX ARC-8s and Dunlop Direzza Z1 Star Specs (both in 225/40/18 and 255/35/18 respectively). The finishing performance touches on my car were an Evolution Racewerks charge pipe with Synapse Engineering BOV and BMW Performance slotted/drilled rotors and fresh pads.
I drove my car with this setup for about 2-3 months and though I now had the throttle response somewhere closer to what I wanted and the power was in the Goldilocks realm for me the car still rolled badly during autocross and the brakes could have been better. I believe other than the PPK's cooling parts (uprated fan and aux. radiator) the exhaust kind of let me down as it wasn't loud enough after a while. I really didn't notice any benefit from the slotted/drilled rotors which were still dimensionally same as stock (more aesthetic than functional). I wanted to invest more money into the handling side of the car with coilovers, sway bar, and an LSD, maybe fit catless downpipes, and an intercooler but the smaller body of the 135i on an E9x chassis wasn't going to allow wider front tires without running crazy camber or Evolution Racewerks' front fenders. My car being fitted with Steptronic didn't help either, it shifted effortlessly, but during auto-x it would never shift fast enough or end up in the wrong gear for a certain turn. I hated how it would automatically upshift at redline, I just wanted it to hold that gear for a bit longer. The lack of an LSD was annoying as it would spin tires rather easily thanks to gratuitous amounts of torque.
During these 2-3 months I start thinking about the '06 Alpine White E46 M3 ZCP that was sitting in the showroom the day I ordered my 135i. At the time it was priced similarly though it had 10k miles on it, but for a 2 year old car now bad at all at the time. That is when my hunt for an SMG E46 M3 began and I will admit it was because I still really didn't know how to properly drive a manual car. I had a friend who let me drive his SMG E46 M3 one night and I was amazed that though slower than my modded 135i it had gobs of feel. I loved how the SMG was very harsh with its shifts in S5-S6 mode but could tone things down in S1-S4 or in the A modes. I loved the induction sound from the 6 independent throttle bodies, the raspy exhaust, the instrument cluster that displayed not just the oil temperature but a coolant temp too. I loved the exterior lines and though older than my 135i still felt right and fast. From that moment I searched Craigslist daily and local dealers.
I came across two shady examples before I found my beloved '04 Imola Rot E46 M3 which was found on Craigslist. It actually was being put up for sale at the Lexus dealership across the street from BMW of Honolulu and sold for an as advertised price of $20k. Despite only 56k miles on the clock it wasn't completely perfect; it had a broken auto dim mirror, a minor dent on the trunk and passenger side door, stone chips all over the bumper and hood, 225/45/18 winter tires all around, curb rashed wheels, no service records, was 17k miles overdue Inspection II, and had 5 previous owners. At this point most people would run away maybe or ask for a lower price. For me I really didn't care as in Hawaii E46 M3s don't show up too often and one that during my test drive displayed no SMG issues or weird engine sounds or lit up a Christmas tree on the dash and only 56k miles sounded too good to pass up. I traded in my '09 135i after parting out the Vishnu V4 and Sprint Booster. Unfortunately I didn't have the stock steering wheel to re-install (sold months earlier).
The day I drove the E46 M3 home was complete nirvana, I was grinning ear to ear despite still feeling like I was on the losing end after trading in my 38,XXX 135i with 1.5 years of warranty left and about $12,000 of mods, labor, and maintenance. All of that seemlessly melted away as I downshifted and buried the throttle merging into traffic. It is now a year later and though I get somewhat sad when I see pictures of my former 135i and the memories and friends I made with it, the M3 just makes me all around happy. Its increased size helps too, not able to seat 5 and a much larger trunk. My M3 has not been without fault though.
Since ownership I have replaced the defective auto-dim mirror, faulty ignition coils, a rear differential (caused by me at the dragstrip), guibo, and an SMG pump. I have accepted these things considering my car is almost 9 years old (11/2003 build) and being the 6th owner. As for performance parts fitted I have installed a new AP BBK, 3.91 geared rear diff, Fabspeed/Supersprint exhaust, Dr. VANOS exhaust hub and rebuilt VANOS unit, and APEX ARC-8s with Dunlop Star Specs (245/40/18 and 275/35/18 respectively). I am not done there though as I have a VF420 supercharger kit, Bimmerworld C&R radiator and oil cooler, BMW Motorsport 55*C thermostat, Rogue Engineering silicone coolant hose kit, Hotchkis front sway bar, and AST 5100 coilovers with Swift springs and Vorshlag camber plates.
Buy a 135i (N54/N55) if you prefer the option of a smoother Steptronic/DCT transmission, love the sound and power of a turbocharged engine, want a smaller body style, require good gas mileage, a warranty, smoother rider, better mods for $ ratio, or more modern luxuries straight from the factory. An E46 M3 is better if you prefer a more raw, stiffer chassis, better handling, don't mind if fitted with the harsher SMG, can do some repairs yourself, have the money to fix the more costlier repairs, want to choose your path in regards to staying naturally aspirated or going with forced induction (supercharging or turbocharging), need more room to fit people or things, or will use occasionally on the track.
The 135i can do well on the track too, but without bigger oil coolers, radiator, the running of water/methanol injection, or a vented hood oil and water temps will send you into limp mode. The E46 M3 can have similar issues, but because it doesn't have the additional heat from two turbochargers it is not as susceptible and most maybe upgrade the thermostat or radiator. The E46 M3 also can have wider tires fitted much easier than the 135i and there are many suspension choices out for the E46 M3 including a true rear coilover setup. It also has a great LSD fitted from the factory where as most LSD's fitted to 135i's will be an ATB setup like Quaife or Wavetrac instead of a clutch type. Things that are subjective, but I am biased is that the E46 M3 both looks and sounds better both stock and modified than the E82 135i and despite the ease of adding HP/TQ to the N54 the induction noise of the S54 and option to stay NA or go FI makes me a lot happier. I also love the 8k rpm redline and SMG over Steptronic or DCT (and I have driven both in an E92 M3 and N55 135i). Also the 135i doesn't feel as good off runflats as the suspension was tuned with the runflats stiff sidewalls in mind so it is over dampened and under sprung if I remember correctly.
To conclude I am including pictures of both my former 2009 E82 BMW 135i and current 2004 E46 BMW M3.