this is my first post on this forum and i am hoping someone rides oregons dunes as i do on a raptor and has been tested by the forest service for decibel levels with an aftermarket exhaust that passed the sound check any info would be appreciated

 

Welcome to the forum. Its nice to see another Oregon rider
As far as the strict sound issues at the dunes no one has been checked in our group Rangers just pass us by searching for those toomey pipes[ lol].. All of us run aftermarket pipes and we ride all the mojor spots regularly and have never had a problem. If your still looking for the magic pipe that will pass try fmf powerq4 with a quiet core insert it will pass but is extremely restrictive compared to not running the insert.

 

The yoshi has three different end caps available, the smallest is suppose to be as quiet as stock or quieter the midsize around 95 96db.You might want to checkout MBRP their new to the atv market but what I have heard so far is good.