[ChkbookMechanic]

The typical things w/ almost all BMWs: electrical system, VANOS issues, etc.

The things I remember most from when I was looking at them were the engine issues with the first few model years (up to 2002 I think). Check m3forum.net and of course, get a PPI. And learn how to replace sensors since the M cars seem to like to eat them more than the standard ones.