I've used wossner and wiseco. Never had a problem with either. I think the wossner is a work of art. Very nice Pistons. I wouldn't hesitate with one. And yes, to get back to original point. I have never used them, but I've heard Wossners are excellent. BTW, we are currently running Wisecos in a 277cc XR250R and a CRF450R. Both bikes are ridden hard.