I have always gone to Pro Circuit for my KX's and my wife's Banshee. Vertex pistons have always been bullet proof for me. I was really hard on two stroke motors and would usually run them till they kicked like a 450 YZF's are a totally different monster though. What do you guys think. I wanna do my top end before I hit Glamis this halloween. My bike has a CRAP-LOAD of hours on it and a whole season of sand from last year.