My buddy drives 17 Mustang GT with performance package, (I'm not exactly sure about their official name, but you know what I mean... the one with 6 piston Brembo, and Recaro seat) and we were out at Grattan raceway last weekend.
We both know the track pretty good, we both have been tracking for about 10 years. Both cars with 6 piston Brembo, and RE71R tires.
I think it's safe to say, Camaro is faster than Mustang on road course.