no cat is the reason, ur exhaust velocity is greatly increased with ur decreased amount of backpressure which will make it sound crappy, as far as the hangers you can get tighter newer ones which will stop the rattling. a healthy exhaust system should not rattle, muffler shells rattle when they need replaced, same with resignators, small holes in exhaust systems and crappy piping. without a cat ur gonna rattle for sure i guarantee it unless youve got something else which is constricting ur exhaust. ive never heard of another exhaust hanger? you can always have a new peice of metal welded onto the piping to move it up or down for relatively cheap at any muffler shop. check the piping around the suspension parts on the passenger side rear tire that is where the mount tends to drop first if ur having any issues. good luck and u cant skimp on ur exhaust system if u want it to sound good, get a good custom mandrel bent system at any midas shop for a good 200 bucks with you providing ur own muffler.... ehh but teho