Based on your recent comments I am confused...
Why can't I take my RX8 and put a miata engine in it and run? Based on the rules as written why wouldn't this be a legitimate option? (I get why you wouldn't want to run a Renesis since they make to much power.) Why not allow those other "excluded" car chasis if they swap to an engine that fits the class?

FYI, as the rules are written now I CAN run my RX8 with the renisis engine and be completly legal.

Stephen