start by reading this even if u dont plan to mod the car http://www.grandprixforums.net/f81/s...car-17482.html ... gives alotta good info on what u should do... any other exhaust mods? such as headers, downpipe? what does the pulley look like on supercharger? stock pulley is pretty basic looking and black in color. stock downpipe is 2.5 inches... if u can get under car and look at downpipe where it connects to catback.. theres a thing called the U bend... u will notice it if its there. if its not it will have a piece of straight pipe welded in.