[der Geist]

I have 7mm in the front and 20mm in the back. Have tracked my car at 6 DE's and 1 AX with no problems. I use the H&R hubcentric on the back and really wouldn't trust anything else with that width. On my 911 I have 2" spacers on the front and 3" on the back, no problems so far. This was necesarry because of the wide body kit on the car. Strictly speaking spacers should make your car more stable on the track and in corners as the stance will be slightly wider.

Skinns101-I don't think you will have any problem at all with the 10's. I am pretty sure you can get by with 12mm spacers but I would get 15's to be sure. The car looks perfect with 15mm on the back in my opinion. I originally had 18" turbo twists with 15mm spacers and it worked fine, not sure what the offset is though. When I got my coilovers I went to 20mm as the tire only cleared the coilover by about 2mm.