disected muffler on 04 500 auto last night, interesting..very interesting!!!! cut exhaust end off,cut off exit pipe inside housing. found 4 welds around insde,ground them out. complete baffle assembly slides out.... just empty shell left. took 2 flat piece of metal same thickness as housing cut out circles the same diameter as insde of housing plus 4 small tabs for welding in place, drilled 4 - 1"holes in plates and off set them inside so holes don't line up together and inserted them inside dividing the housing into 3rd's.. weld it all back up outside(left out exit tube cut off inside) and back on quad...cool sound not too loud,,,sounds close to a flowmaster[img]i/expressions/face-icon-small-smile.gif[/img] have not rode bike yet to see power difference...can't waite

 

There is a muffler mod that even has pick with it that has been used by a number of Cat owner with good success. Just do a search for muffler mod.