Up here in New England most of the trail systems go through somebodies private property. I've seen trails closed because of loud aftermarket mufflers and 2 stroke high pitched sound. I like 2 strokes. Had one myself but learned landowners don't care for the high pitched racket. Sold it as I don't want to tick off the landowners and have them close trails.

 

exactly as moose says.

if you ride in the desert dunes or in the middle of a deserted forest, then loud pipes and 2-stroke fumes aren't an issue... but when you're riding trails that put you close to a suburban area, you need to have common sense about what you ride, what time you ride and where you ride- it's just a matter of being courteous to the community around you. these kids love the sound of their pipes and want these built up sporties, problem is, there's no place around here to ride'em- no place. Especially around me where the trails literally cut through farms with feeding livestock and horses.

I'd rather ride a quiet atv and not be pissing anyone off, than riding a loud atv and bringing attention to myself and getting trails closed.