Really depends on how you will use the car.
On the streets (fast/furious/accident) ~ 335i. You will have the world of modding at your feet. $279 bucks can net you 80 fuqing whp. I ran next to a M3 off a light and I just pulled a 1/4-1/2 CL in front of him and he couldn't regain that distance...I am sure after 100mph he would start gaining, but in the streets that is unlikely. Reliability is much more an issue than it is for the M3. Most people (women) can't tell the difference between the 335i w/ some cosmetic mods and a M3. I am a nostalgic/romantic, and hated M's move away from the inline 6...the 335i is its last hurrah...saying "3 liter Direct injection, twin turbo inline 6" makes me get a hard on. MUCH BETTER DD (and customizable car) IMO.
Around a track (don't have to worry about fitting a LSD, new suspension, tires etc) ~ M3. It has its own feel and purpose. You will LOVE revving that NA S65 LIKE IT WAS MEANT TO BE (you'll find the torque in the revs...but MPG will hurt). It is exclusive. You won't see 20 year olds (like me) driving M3's as often. It takes the beautiful E9x body and makes it go to the gym and gain bulging muscles. Very linear power delivery...but imho, lacking the sensation of speed. I wouldn't mod a M3, it was made to accomplish right out the factory. MUCH BETTER PERFORMER/SPORTS CAR.
I am sure the 335i hurt M3 sales, but the M3 was made without limitations in mind, while the 335i was retarded (lack of LSD? Really?) by BMW . The 335i is a very fast sporty car...while the M3 is a sports car.
In conclusion,
Daily Driver?
335i > M3
Track/Weekend Warrior?
335i + mods > M3
JK
