i know what you are thinking, it increases the gear ratio so you loose top end. this is what I have read; that with the aerodynamic drag at 130 mph you need much more horsepower to excellerate. Everyone knows that right. but with a 4.10 you have a higher rpm at that speed at which you have more horse power to get you that one mile per hour faster. Like I said I heard(read) this to be true. I didn't say it actually was.