Stock exhaust here too. I just ordered an axle back muffler delete with 4 inch single tips. With the stock valance I measured 5.2 inches for the exhaust tip or 5 inches max. I couldnt find anything with duals that would fit. Carving it out will probably look awful imo. I am hoping the large 4...
I would bet it's not a typical pot but an optical encoder. A dirty wiper on a pot causes noise when adjusting so is a poor choice these days for that purpose.