Get an E46 M3 that has been well maintained, and don't look back. If you can find a ZCP even better. My friend's Interlagos Blue E46 on Pilot Sport Cups was the only car to ever scare me in a corner, that thing was so brutal it made my (at the time stock RS4) feel like a FWD A4 lol. Massive respect for those machines.
Current: Alpine White F10 M5|H&R springs|12mm/10mm spacers|Eisenmann Race
Sold:Imola Yellow RS4-KW V3|MTM 10mm spacers|Hotchkis rear sway bar|APR Stage 1|Milltek Catless|RNS-E|Euro RS4 Flat bottom Steering Wheel