MrE,
I am not sure whether this is as critical on a Fiero chassis, but typical seats for a Countach are usually too wide and too tall as well as too high. The Procar Sportsman Pro seats are a good solution that I have found. They look correct, are plenty low, and are available from Jegs or Summit for under $200. I get them at OEM pricing but you are better off with them and free shipping. Another $100 will get rid of that cheesy velour insert. The carbon fiber material around it looks really nice. Most aftermarket seats are 22"-23" wide and these are 21", and most of them are 36"-37" tall which hits the roof and these are 34" tall. That does'nt sound like much difference, but I have found it to be a big deal. They come with adjustable tracks included but you can get another 1-1/4" of headroom by bolting them directly to the floor.