I say those values are a little high. Every car is different, but I gained about 30-35hp with: Pullies, T/A, FIPK, Aluminum D/S, 4.10, Long Tubes, O/R X, Mufflers and a stinkin shifter. However my car is a little light with its CM K-Member w/ coilovers, no hood liner, no trunk carpet, no back...