Only because 2stgTurbine in the previous post specifically mentioned the Cup car. I agree with you on Spec e30 and Spec Miata. However, e30 still is faster and cheaper to be towards the front of the field. Front of the field in Spec Miata can get crazy with $15k motors. My biggest issue with the Miata is fitting. 6'1" is uncomfortable in a helmet in that car.

Best track performer for the money out there imo: Camaro SS 1LE. The only stereotype you have to combat is people think it can only go in a straight line.