I would be in for anything 370-395 range. I think best case would be to change each gear ratio as well, but I would be willing and happy to start with the rear first and see how it does with everything else stock. I'll even volunteer my car as a guinny pig. A mustang gt came up on me trying to race yesterday. I ignored him like most others, confident that I had nothing to prove and then he guns it. The supercharger kicks in very loudly on that cobra and he is pretty quick. I'm glad I didn't race him. I just smiled and waved. I think the gearing gives a lot of advantages to a lot of American cars, because they don't have to worry about going over 115mph, so they can get there quick. LOL