Spec MX-5s race within SCCA and NASA rules generally. For example, Spec MX-5 cars can run within the SCCA STL rule set or the NASA ST5 rule set. However, to be eligible for Spec MX-5 specific prizes and awards (e.g. Spec MX-5 Challenge points), Spec MX-5 cars must comply with additional detailed rules published by Mazda. The specific technical rules for the cars that govern Spec MX-5 (e.g. Spec MX-5 Challenge) competition are contained in Mazda’s Spec MX-5 Rules and Regulations. A PDF is available here.