I was suprised at the extra hp I got after the exhaust change out! Mine cost $250 and it was well worth the money. I had already done a 2 inch body lift, made front and rear bumpers out if 2" pipe, and 275/75/15 tires on bigger rims. I had a significant loss in performance after I did the wheels, tires, and bumpers. I think I've gained that loss of performance and then some back!