sparkarrestor/baffle
#3
I took mine off along with my airbox lid and i could tell a very noticable difference. The baffle just quiets the noise coming out of the engine. The noise could cause a problem on certain trails though for passing the noise limits. The spark arrestor doesn't let sparks pass out of the muffler so it won't start a fire, most trails require spark arrestors.
#4
Yes it's perfectly ok, almost everyone does it. When you do sell it to me for $10. I need one to put in my daughters ATV. I'm trying to make hers back to stock. [img]i/expressions/face-icon-small-smile.gif[/img]



