I went from the 3spd automatic to a t-5 5 spd and just love it. Except for shortening the drive shaft and having to put in a clucth and the clutch linkage It is the same as changing an auto trans. With your 3.08's and a .63 overdrive you would probably be turning 2000 rpm @70-75 mph. If you have a console that would also have to be changed, and the manual ones can be hard to find. Still worth it in my mind.