I'm running the std. wheels off a '98 M3, 7.5" front, 8.5" rear. To come as close as possible to the stock E30 M3 tire size, I'm using 215/40's up front, 245/35's in the rear. I got some minor rubbing on the driver's side (slightly rolling the fender lip solved that). Drawback to using the 245's on the rear: There's only one choice for tires: Pirelli P-7000's. Still, it's been a good tire, grip is fine, and my first set lasted 20K miles.