What type of driving you planning on? M3 is nice and flashy and the v8 sounds awesome but if you only plan on driving it to and from work/school then you're not really getting the most use out of it imo....unless your plan is to drive it up and down the downtown strip and show it off to the ladies. You'll be wasting gas since it sucks up a lot of fuel. In that case I'd go with the 335 where you feel that low end torque that the M3 lacks. You'll get pretty good gas mileage compared to the M3 so you'll be able to use the money you save to buy a piggyback tune which will allow you to smoke the M3 if that's all you are trying to achieve.
If you get a chance to drive both the 335 and the M3 on the track (not dragstrip), you'll be able to appreciate what the M3 is all about. And if you plan on tracking your car a few times a year, you won't regret going with the M3. At least that's how i feel.