I have a 140mph one in my 90 GT, I have someone interested but if he backs I will let you know. I might be getting a 91 GT also soon..that I may part out depending how badly wrecked it is.
The 87-89 are the same as far as the warning lights etc. In 89 they went to the higher speedo...but it was in the middle of the year. 1990 they changed the cluster some when they went to the airbag steering wheel. You CAN use a 90-93 in an older one though, a few of my friends have done it.