I have used the 2 speed hammertimes in my RX-1 Turbo at 15 pounds boost & also in my Attak. They actually feel slower but the feeling is decieving. It is a strong linear pull that was the quickest/fastest clutching I ever tested in either of my sleds. What "FEELS" faster is usually slower!!! A strong linear pull at optimum rpm,s with out belt slip is the best performance your gonna get. Got that with hc,s but the stock clutching also worked well with tweakage!!! The one thing that Al(ulmer racing) can do extremely well is in after service sales which supertorquer is not in hi regard for. If your not an experienced clutch tuner call Al!!! Hell; even if you are experienced still call him!!!!m If you have the time; energy & experience you can tweak anything to work well with the emphasis on time. Pick a vendor that will help you tune your clutching in 100% as that is where a trail sled will see it,s biggest gains.