A day before my first off-road race ever, I was a nervous-wreck because of many reasons. One reason I could pinpoint was that I knew the pipe on my 2004 Honda CRF250X was no where near sound legal. In the AMA-regulated National Hare & Hound Series, a bike must be no louder than 96db and is subject to sound testing. FMF equipped my race bike with a Q4 Muffler and spark arrestor insert, which calmed my delicate nerves and pre-race stresses a good amount. Honestly, my bike was so loud before it just felt like I was constantly hitting the rev limiter and going to blow up the bike with even the slightest twist of throttle. After installing the FMF Q4 muffler, I could feel and hear when my bike needed to be in the next gear. If your bike has a stock pipe, this muffler will enhance your power and if you have a loud pipe, this product will allow you to save your hearing and deliver smooth power while complying with noise regulations.