Hi Terry, thanks for getting the profile done.
I can't tell you a whole lot on the 84-89 cars. I have heard that quite a few parts are interchangeable thru those years. There will most likely be some people replying to your thread. Things get slow on the weekends some times. If you haven't already tried the search function, give it a try. Alot of the oldtimers will expect that you've tried searching. A forum member named az-zbum here is quite knowledgible with the z31's (84-89)
Another site that gets quite a bit of traffic is
www.z31.com.
Sorry I couldn't be more of a help.