if you intend to head to the track with it, id get a C34. its cheaper, better support for power mods, can get AWD manuals. the M35 to me isnt something youd take on the track, its auto, the box is a little sluggish (but that can be corrected) and there are cases of factory cars with bad cooling systems. anyway, thats not to say they shouldnt be on the track........
ohh yeah +1 for AWD, a little harder to get off the line, but good for powering out of corners in the wet