Sorry BJ, I understand now that what I tried to say wasn't very clear.
The rules are very clear about what cars and what mods on them are allowed in the specific classes. They are designed to keep things straight for the guys at the national level where everyone builds their cars to the limit of the rules.
Some folks run street tires and only have a single mod (like you) that places them in a class designed for cars with tons of radical mods and race rubber. No distinction is made between them within the class. Its one size fits all per class.
NASA (National Auto Sport Association) rules change the pax multiplier based on each individual mod you perform including whether or not you run street rubber or race rubber.