Installed on my 2010 KX450 and quite pleased. Installation was easy and I recommend the FMF heat shield. I've ridden a few races and the sheild have protected my pants. Sound great and is a little quiter than stock muffler.
FMF Factory 4.1 titanium muffler combined with the stainless Powerbomb head pipe unleashes your motorcycles full potential with massive power increase and substantial weight savings. The combining technologies of the Factory 4.1 muffler and the Powerbomb header have been developed to compliment each other's power characteristics to provide a complete exhaust system that builds power over the entire range.FMF Factory 4.1 Muffler