Just I note on this...I had all the throttle body apart and checked to see how the butterfy moves in realation to the pedal. As far as I could see there was actually no delay in the butterfly responding to the pedal. I think this add-on must be giving disproportionatly wide butterfly movement for the initial few degrees of pedal travel. You might find that it behaves differently between an Autostick and a manul too since the former usually have a linear response and the latter have rising rate respones. Not sure if this is the case with the xfire though.