[AckM3]

SMGII absolutely shines at the track, S6 on a road course was always where I appreciated it the most (on the street it was always a bit clunky). I never had problems myself, but do keep in mind that it's expensive to fix -- not the clutch itself, which is the same as the 6MT, but the hydraulics that operate it. Also, the e46 M3 in general is quite pricey to maintain if you track it regularly. It's heavy (although not as heavy as the new car), and you'll eat through pads/rotors/fluids/tires etc. Have you considered an e36? Or is there a specific reason you want SMGII?

BTW there are a bunch of peeps over on m3forum who track their SMGII, maybe ask in the track section over there. In particular, member Antroiny has a properly track-prepped car (cage, seats, harnesses, reinforced) SMGII car that is still street legal, I don't think he has pics of his build up but you can PM him.