Does anybody have this installed on their car. I have a friend who is a very good transmission rebuilder so I was wondering if this has made a very big difference in shift quality and amount of time car takes to shift. Also will it make the trans last longer.

INTENSE sells a good one at www.intense-racing.com and I believe ZZP does also. It will firm up the shifts very well, reduce the amount of time to complete a shift, and will save wear and tear on the clutches. It CAN and probably WILL increase the abuse on the diff.