I'm fairly stock -see sig-. I dyno tuned my car and got 7hp and 6lbs of torque; that's more than I ever would have expected. Only reason I did the tune though, is for the 4.10's (speedometer correction). I can't say for sure if I felt a power increase, since I was still getting used to the gears. The first pull we made w/ the chip looked like it might have made closer to 8-9hp, but the motor detonated at 5200 - the tune was too lean. I can say that the tune made my car seem more smooth and responsive.