i have been looking into 4.10 gears and i got a price of $525 installed for everything(price of $1300.00 from the dealership). That price seemed pretty fair to me. The guy who is doing it was a ford mechanic and they use ford parts. I was told by them that with a Xcal2 tune that i already have that the tune will adjust to the new gears. Anyone have an experience with that?