What Is the difference between the 2004 ImpalaSS and the 2003 Grand Prix GTP? I know they both got the same engine and transmission, but ive heard that the GTP is faster. Do they have different PCM's or what?
mos tof the difference is sheet metal, same eninge/trans, if anything a 2dr GTP will be quicker (lighter by about 300#s IIRC) the #s should be almost even on the 4dr GTP. The Imp has larger front rotors than the GTP does. Other than that there are a few conviences that the GTP has that the SS wont (HUD/perf. shift come to mind).
Also the Imp has a lighter Alum cradle as opposed to the steel one on the GTP