after looking for a year I found a good shop in Ontario Canada that did my muffler mod in one day.$800 dollars Canadian ,open sundays ,excellent welding .they removed existing mufflers/exhaust as a unit ,cut into each muffler and cut out one pipe and rerouted exhast with new pipe to eliminate exhaust going thru some baffles ,rewelded and reinstalled ,louder note ,no drone ,a few more hp I think , write me if you want their name , I can send pics and video ,happy driver,,heinz mayr