Just to clear up some potential confusion here, there are 2 similarly named Toyos being discussed here: the T1R and the R1R. The T1R is a genuine high performance street tire, with a comfortable ride, decent wet performance and some semblance of tire life. The R1R is a max performance tire aimed at the street tire autocross classes that is much stickier, stiffer and shorter lived. The R1R on the track on heavier cars will blister fairly easily, as it is designed to get heat into it in the short time of an autocross run. I suspect, but don't know, that it would be OK on a 7.