Aerodynamics and downforce don't get discussed much aside from hood vents.
As far as I know, nobody has ever put a front splitter on a fiero. I would think to do this properly you would need a closed chin spoiler first and then add the splitter underneath. For those of you why do not know what a splitter is, here is a picture.
It works by forcing air over the car instead of letting it go underheath. The fiero nose with its upward angle is really bad for forcing air underneath the front end. Its probably the biggest cause of front end lightness at speed. With a chin spoler and splitter, there might not even be a need for a hood vent, but the more air you can get up and over the car the better.
Canards would also help with front end stability and downforce but I think they might be a bit overboard for a mostly street driven car. Most people would associate canards with a ricer although they are on quite a few road course cars.
Hood vents work well on a fiero. Instead of forcing hot air under the car from the radiator, you can vent some or most of it out of the hood. I think most hood vents on fieros are too small to get the most benefit, but everything helps.
Driven Visions (www.drivenvisions.com
) makes one of the better aftermarket fiero hood vents I've seen. Its deep and has good size vents.
I'm not sure if a traditional wing will work effectivly on a fiero. It would probably have to be 12-15" high to be in a clean air stream to work. The fiero rear window created a big low pressure area and a bunch of "dirty" air. The IMSA "whale tail" spoiler is another option but I'm also unsure on how effective it is. Its design looks like it prevents air from flowing up the back side of the car into the low pressure area. Anyone else have insights on any testing?
The major aerodynamic flaw of the fiero is the flat rear window, but it also serves a purpose. It promotes airflow through the engine bay by creating a low pressure area which sucks out hot air.
There is lots you can do to make a more stable car and help with handling. Maybe I will make my car a guinea pig and start adding some of these parts and report back on road feel.