A cat-back muffler from Magnaflow, electronic, with outputs on the right and left, produces a very pleasant and calm sound. It's installed on a 2014 GMC Sierra. I swear the muffler has no complaints. The sound is not annoying; it's calm and melodious depending on how much you press the pedal. Purchase price: 1500, selling via highest offer. Note: Selling the muffler alone without the two outputs.