I have an ’86 Porsche 944 with an LS1 engine swap. The car has a full interior and essentially stock suspension. It has 17″ Cup II wheels with DOT R tires. From reviewing the rules, I’m guessing this car will class as Street Modified. Does that sound right?
Not an expert on classing, so maybe someone else who is will reply, but you can register in Street Modified and change your class at the event if someone says it should be a different class.
Two seat cars with full interiors would go into SSM, SM is four seats. The DOT-R tires put you into SSM, everything else but on 200 TW tires would put you into XSA assuming the finished weight is over 2750 pounds, XSB if 2100 to 2749 pounds.