If you are gong to do that I would go with the 12 valve. The 91, 92, 93 is the motor of choice if you are looking for speed. They come from the factory with a gnarley cam already. (The tranny has a better input shaft also....High horsepower will pop the input shafts when you hit lockup...)The downfall is the pump sucks on them. If you can find that motor and put a P Pump on it you are in buisness. The dark side is much cheaper to hop up. I am new to the psd market but know ALOT about the 12 valves. If you have any questions....just lemme know.