Quiet Performance Muffler

[Shadowfire]

With a big bore kit, you need something that can flow the exhaust without excessive restriction AND has enough surface area to absorb the sound waves (change them into heat). You just need to do your research before purchasing the muffler. In order to effectively quiet up a higher flow rate, you basically need a bigger muffler section. If the performance muffler has a muffling section of similar volume to the stock muffler, its likely to be louder than the stock pipe.