I just put my Mr. Mike's on, so I've got one good grey cover. Ignoring the horribly torn one, there is some dirt on the good head rest, but it seemed to come right off when I scratched it (I haven't tried cleaning it). My guess is just hairspray or something from a passenger.
From my before photos:
Only caveat is that you'll need to re-use the back area foam from your current seat cover. Mr. Mike's instructions had me pull those two pieces of foam off the covers, and re-use it with his. You'd have to do the same. I'll throw Mr. Mike's DVD in too. His covers attach at different places, but it will still probably be helpful.
1987 Fiero GT : Information | Gallery