Sprint Booster Installation
Wayne talks about this in the 101 Projects book. Basically it shortens the throw of the pedal so you get to wide open throttle with a shorter depression of the accelerator pedal. So instead of pushing it all the way to the floor to go to WOT you only push it a little bit.
To me it seems like it would be twitchy, but I guess you could get to WOT faster if you only had to push the pedal a little bit instead of all the way down, which would take longer.
Steve