I have had 3 m3's and the e46 m3 would be my choice with out a doubt at all..
This m3post forum is heavily heavily biased on e9x vehicles... just look at the small ass section for e46 ....
With that being said...
PROS: Larger/more hp/newer/less issues
Cons: gas sucks/cost twice of e46 m3/parts cost more
PROS: way better gas mileage/easier to park/parts cost less/timeless look
Cons:A little smaller
e46 m3 Black
Too many mods