My wife has a 2006 yfz450 with just a pro design intake kit and no air box lid and no baffle in stock muffler and jetted correctly. We were at dumont dunes in CA and she was beating banshees, one banshee I talked to the guy he had t5's, vf3, and a fresh top end with wiesco prolites and my wife pulled him. I haven't raced her since putting in the 400cc stroker yet. When we do I'll let you know the results.