Oneida makes a sound filter they claim reduces exhaust noise by 6-7db. Has anyone tried to see if the muffler is comparable with CV's 18" filters? Here is a link to their product.
18" Stacking Sound Filter
https://www.oneida-air.com/18-inch-stacking-sound-filter
18" Stacking Sound Filter
https://www.oneida-air.com/18-inch-stacking-sound-filter