[C5GTO]

Have you looked into the Audi transaxles that a lot of GT40 builders have used? I don't know the specifics myself but have heard they're available at a reasonable cost and if the gear ratios work in a GT40 then they should also work for your car.

My opinion on the latest stretch is that it's too much. I think you'd be better off finding a more traditional transaxle and not doing the extra stretch.