Thanks for the photo. You are very helpful. I have two gearboxes. One has extra webbing which i think means its s1 turbo but would like to make sure.
There is a way you can check for sure that you have an original gearbox. Take the end cover off to reveal 5th gears. I have reference to the number of teeth on each gear. 5th gear was unique to rs1600i. All you have to do is count the teeth. James