Lemme try! Before Greg gives us the real info:

Stephen - yes on your two comments. Greg asked for the Renisis to be removed, and the committee decided that they would just handicap it instead of that. Lower weight but I am assuming an educated guess on how much power they took away.

The addition of the Type R engine includes a weight penalty assuming because the cam spec is outside the rule-set? Interesting.

Chuck - your fully IT compliant car can run in STL provided it meets the engine size requirements (non ITR) no matter what rule is or isn't specifically compliant in STL. It just has to be 100% IT with no mixing and matching or rule-sets.

On edit: I wouldn't put a dime into an RX8 for STL right now. There is committee issue with the motor design, and RWD adders keep on rising. A good plan would be to run one in ITR for a couple more years and see what happens...but just like in ALL National classes, you win the runoffs, expect a lead trophy (or RP or...).