well, going from 3.64 to 3.91 is a dramatic difference... and shift points are reduced. Personally, I can't really imagine them shifting sooner than that. I think I'd figure out exactly where the car would be shifting at 4.10 or higher. Right now, I'm at 75mph at 3000 rpm in 4th gear. Third is 55mph at 3000, meaning if I redlined 3rd it would hit about 110mph, and that's a lot lower than before. 4.10 or higher might make that even worse.