After a few weeks of reading in the forum what were the best gears for my stang, i decided to go with 4.10 and i have to say that i think it was the best decision, the car feel like i have 300 HP ! but i don't have the tunner, so my speedmeter is off, yesterday i was driving 130mph but i dont think that was the right speed, Does anybody know by how much my speedmeter is off ? ? Thanks.