thats because the stage 3 comes with forged internals, but you have to have them installed. I say do this. Get the hahn stage 2 with fmic, its $3000. that will teach you alot about your car and you will be a lot more comfortable working on it. I dunno if greddy makes an intercooler for the 2gnt, and If they did I couldnt see it being much better than the one from hahn. I can't remember what core the hahn ic uses. So get the stage 2 in, learn stuff, blow up your motor, then rebuild and run more boost! thats what i did... :thumbsup