I have a 2003 gtp and recently had to replace the engine and trans, and my exhaust flex pipe was busted so that was a good time to do headers as well. I ordered some no name knockoffs from ebay. They seem to be decent quality for as cheaply as I got them and surprisingly bolted perfectly in place with no massaging required as I have had to do with speed daddy headers I have used before. My problem now is that I have exhaust leaks at all the slip fittings where the exhaust sections join. It seems that the larger pipe is too much bigger than the smaller pipe so whenever I put a clamp over the big pipe it doesn't pull close all the way around so it doesn't seal. Does anyone have any ideas of what I can do to remedy this problem?