I just put the Mag force in my 850 pro they really do work awesome and my sled performs and dose everything they claimed it would be. I just ordered the exact same setup for my sons 850Put a needle bearing in the clutch. Only change. No more pop from the engine in and out of throttle. Throttle response is fantastic. The mid-range feels really strong now. I talked to SLP about clutching and I am going to try the SLP magnum force weights. I have the new BooneDocker weights in it now. It is running fantastic just want to try SLPs recommended set up.