I think you'll find the intake manifold (specifically the middle section and the plenum) on the fieros is what kills hp and makes all that low end grunt.

Otherwise there's a lot going for the car - slippery, wide track, 4 wheel discs, a ton of torque, short wheel base, easily repaired body, only 'heavy' weight wise, GM mpfi system easily reprogrammed at home these days, pretty stiff chassis, and still a lot of cheap donor cars out there for parts.

I have yet to see any ita fiero show up that has really been built to the limit of the rules (or extent that the front running cars have)