I found a GTA with Perfect Tan interior and carpet and just so happen my 83 is bare on the inside. I got all the full GTA interior now but I'm noticing that it looks like alot of the holes for where stuff screws in don't match up I haven't started yet but do I have to do anything drastic to make the plastics look orginal in mine.

Also what is the best way to clean the carpet and relay the other car's into mine, anyone know a good link or place to find what ill need for insulation and adhesive. And yes I know the guages are different mechanical to electrical I'm not messing with hit till i get my 4th gen dash in.

It will all fit, yes. But for the early 3rd gens, some of the mounting tabs & holes don't line up with later years.

Nothing real drastic, from what I've heard. Never actually done it myself.