I'm...not too sure why you would do that. The reason RX-7s perform so well is because the car's light. The Supra engine is heavier than the RX-7's rotary, and would probably weigh the front down a lot more than it was designed to perform with. Why not just put an enormous turbo and intercooler on the existing engine?Hopefully two summers from now I'm going to have enough cash to buy a 1993-1995 (Gen 3) Mazda RX-7. It has a rotary that I'll probably swap out for a Toyota Supra engine (I forget the engine designation) that will definitely get reworked.
[EDIT] And for the record, my ride is a pair of Firefly Zeal 2s. Nice comfortable shoes, like...