FWIW we run the Rivals on our crapcan Miata, and I'm happier with them than I am Z1s in the same size. we ran a full 24hr event and used up maybe 25% of the tire. I never ran that car with DOT-Rs, but I was quite happy with how it handles on the Rivals and was keeping up with well-known SM builders & racers in their 'cheater SM car'. (they were also on Rivals).