I agree - we have an E46 M3 vert and the harsh suspension makes it a boneshaker as a daily driver especially on the lunar landscape of the streets of Boston.
I prefer the E46 shape but my money would go to the 335 - same power, more comfort. You can also add Procede software for not much $ to get sizable gains if you need it.

0-60mph in 4.5
¼ in 12.8

http://www.vishnutuning.com/bmw_zero.htm

We will be selling the M3 in '08 and will probably replace it with a 335 vert + Procede