We'll this is why I think my cat is bad. I switched my stock muffler with an ebay after market exhaust pipe a few months ago. When it was switched, there were carbon rock or black rocks that came out of the muffler when it was removed, and some shot out when the exhaust pipe was in and they tried flooring the car. BTW, I am not planning on getting everything I mentioned right now, those were just part of my plans so everyone can have some idea what to tell me. But I was really thinking of getting the Cat Back system right now, if I need it.