[Ryephile]

The R888 was a great dry-warm-weather street tire, I ran it as my summer/street tire on my Exige S. The R888R uses the same compound, just a new carcass and tread. That tire in a 315/30-20 would fit the rear with the right wheel (11" width, et43 or less).

Also, this might be a surprise, but consider the SS 1LE and ZL1's Supercar 3 tire. 305/30-20 rear and the ZL1 guys, with similar power to you, seem to be fine with it.