Originally Posted by 10grabber horse View Post
I have 3.15 s in my 2013 auto gt would love to go to 3.55 or 3.73 . Track pack cars have 3.73 with 19 inch tires & some other goodies.
3.55's or 3.73's in your auto would not make your car any faster. You have almost the same gearing as the track pack cars with 3.73's when you factor in the gearing with the 6R80 auto. In fact your 3.15's combined with the 1st gear in the auto is actually steeper than the MT82 and 3.73's combined 1st gear.