when i bought my gsr it already had a hi-flo cat on it. But there was no new header or exhaust, just a muffler. And the cat fit perfectly. Well now i went and bought the DC 4-2-1 header and the Tanabe RM exhaust and for some reason the cat won't hook up right to the header. I went to an exhaust shop and had them hook it up but there was no gasket to put in there and the guy at the exhaust place couldn't even hook the two together to fit properly. So now i have no gasket and the fittings don't fit correctly so i have an exhaust leak that i have to keep putting exhaust sealant on. I want to get it fixed right but i'm not sure what i should do. Does the cat not hook up right because its fitted for the stock header and i have to get a new one or what?? I don't know..someone gimme an answer here...thanx