Well the rattling or clunk noise got louder and decided to look underneath. I saw one of the hangers that holds the muffler broken,so took it to the muffler shop. Well at the shop we discovered that there was two large holes were one hanger broke off and got lost and the other was just hanging by a thread. The the thing is that Saleen decided to weld the hangers from the muffler body were now it makes sence that it would break off sinner or later. So muffler shop patched up the holes and welded on new hanger from the pipe where it would be stronger. Well just giving you guys a heads up. Oh yeah the muffler that was most affected was drivers side.