Ok well I'm not gunna lie I'm still pretty new at modding my car, i mean i do know some things self taught mostly but i still like to learn few more things and how things work on a car. So I am proposing a question to any who can answer me. Before my G6 i owned a 04 GP GT, and I had put a performance exhaust and dp on it, supposedly adding close to 30hp maybe? but anyway my mechanic was talking to me when he was putting on some parts for regular maintenance and of course noticed i had put an exhaust on it. First of all this guy can work miracles with cars only wish i knew a fraction of what he knew. Anyway he explained to me that just putting an exhaust doesnt add any power to the car, only upgrading the components in the engine will. I mean it kinda makes since to me and i trust his opinion. but the manufactures of the exhaust say otherwise on their website. So my question is can anyone explain to me how adding a exhaust adds power or if it does at all. thanks alot.