Have installed more than one, had zero problems with any of them. All of the serious racers run V-Force as they're considered a bit better than the Rad valve. No jetting changes needed on either a CR250 or a YZ250 raced in the midwest. I think maybe RCannon's bikes had other problems and that explains his results. As with anything intended for racing, you've got to start out with a fresh motor, good seals, correctly jetted. Yes, you will notice a performance improvement, especially on a 125. Broader powerband with a bit more hit to it is what I got.