Not to much my buddy that I ride with said its loader when hes behind me.All I did was make it beath easyer I didnt take ant baffles out of the muffler..

 

Bill35
any chance of back-wash getting in your exhaust deep water riding or washing-off the ATV with a hose?
could water make it's way back to the engine?
-MT

 

Sure I guess theres a chance that you spray water from a hose up there that kinda why I left the bottom open giving It a place to run out,If you look at most your after market mufflers that all they do is cut down on the back pressure.As far as deep water riding as long as you keep it running youll be ok...