Originally Posted by adc
As a little background to my ownership situation, did Euro delivery both on the 335 and on the M3, drove both on various track (including the Nordschleife) and had both cars lightly modified: a chip on the 335i and muffler on the M3. As far as street driving, they were both my daily drivers (the M3 until recently).
Let's start with the 335... I loved the sound, power delivery and tuning capability of the 335i. It can be made quite quick for very little money, has excellent tractability in town due to the torque and good throttle response (very little lag) and definitely gets better gas mileage than the M. It's a good car, responsive, adjustable, not much understeer, a class act. On the debt side, the runflats are complete rubbish, the suspension inadequate (especially tuned), the open diff spoils the fun and the reliability suspect (mine had wastegate problems since day 1).
The M3 is simply put in a different class in all these metrics, except fuel economy. It rides better than the 335 with the EDC suspension, sound even better and the throttle response is absolutely incredible. It's the Ferrari of the sport sedans, no doubt about it. Compared to previous M3's, it handles better than the E46 (better damping and less understeer) and than the E36 (better damping and possibly less understeer) but of course feels a bit heavier than both - because it is. It has a very throttle-adjustable attitude, especially in faster corners (you have to be quick to respond in the slower corners), it works with you well beyond the limit and this makes it a very confidence inspiring car to drive in all conditions. This very poise and confidence is what makes it such an incredible drive in the rain, even on track.
If you are looking to marry the 335's daily driving capabilities with the M3's suspension/handling, then the 1M is a good compromise - with the added bonus of a significantly lower weight than the M3. It has most of the M3's suspension bits, comes already tuned from the factory, and is super-rare. A future collector's item IMO. The 335is might also be close, but it still rides on ruflats and has an open diff (and is expensive).
Hope this helps...
I can't write much but suffice to say it just feels like another class of car.
Although I think the 335i is the best value in its (own) class.