Im running a 205/50/15 Kumho Ecsta Supra 712 and I fucking hate them no grip whatsoever. The have more gip in the rain than in the dry just about. Ive heard of some people running up to 215 and 225 however only certain offsets will be able to handle a tire that size and not rub and obviously it wont work if your car is slammed on its nuts.
Robster