Will C4 or C5 seats fit in a 3rd gen ('86 IROC)? I've seen repro 8" IROC wheels in a magazine. Does anyone know if anyone makes wider IROC wheels (9 or 91/2 wide)?

 

The seats are not a direct bolt-in. However I have seen it done and it has been discussed at this site before. Maybe use the search feature for info on the seats. You may have to swap out the tracks. (put vette seats on f-body tracks)

I've never seen a repro Iroc wheel that is wider than 8". They make them in diameter all the way up to a 20".