super66 hasn't been back on, for awhile.
I purchased this unit from him and did a DIY installation thread.
I like it, but it had a major issue with fitting the OEM shift knob on the 987.
There are several places that have them on sale, the best deal is here -
http://www.eagleday.com/scca99shshki.html
It comes with a replacement for the plastic cable end, but Rennsport says this replacement is BS, there are no complaints of breaking this part on 987s. I Don't know about the 986 unit, but hey, it's there!
I would call and make sure your shift knob will fit, before buying one.
Take your time adjusting and fiddling with it, and you'll be happy with it.
I love mine.