Ok I'm trying to find the difference in the 87-88 harness (yellow) and the 89-92 harness (grey). I would like to know the benefits "if any" of the two. I would also like to know if its a good idea to switch from yellow to grey, and can I use a grey harness/w ecu on an 88 supra. I know it may be out there in this question but there is never a dumb question just dumb people! Lol any incite would be greatly appreciated.