Everytime I hit a bump, I get a clunking under the passenger seat. This problem is more pronounced when I have a passenger in the truck and has been there since I test drove the truck. That day the dealer said they tightened a shock up and believe it or not it did go away until about a week later. I went under the truck have found that at the front edge of the muffler exactly where the crimping is that it is only about 1/8 inch from a sheetmetal screw going into the floorboard (holding some kind of plate). Also the nuts on the clamps look like they were tightened that day by the dealer. I don't think there is enought play in the components to loosen the clamps and twist the muffler or anything. Has anybody else had this problem? It seems hard to believe I'm the only one. What would you do? I don't want them prying and bending stuff. If I get a new muffler like a Magnaflow is it shaped differently enough to probabally fix the problem? That shouldn't void my warranty will it? I have no other mods.