I built a street fiero 4 cylinder when i was 15, from the ground up, and I can tell you i think there is some major potential there. Most of what i did was IT legal, and I ran the stock throttle body and it reved very nicely. Finding or having a really good header for it I think would be the key, the stock exhaustmanifold is horrible, I just reworked mine, and ran a 2.5 pipe through a superturbo muffler, no cat, and it was fast. kicked the butt of all those guys with their 16v vws. The horrible suspension is easily fixed with the delrin bushings for it. did not really do much with the cam or the compression, but i swear it was as fast as a lot of v6s. But if your gonna build a fiero, i think the V6 has more potential for its class.