I read an article in Dirt Rider on that exhaust installed on a YZ426F. They said that it quieted the Exhaust from 102db to 98db. AMA legal is I believe 100db+/- 2db for motocross. And for offroad I believe its 98db +/- 2db. I think the CRF isn't quite as loud as the YZF,but I think the Q exhaust is an excellent decision. Noise awareness helps protect our right to ride.