This is directly from the website:
Throttlepak is a device that modifies the speed and degree to which the throttle body opens the throttle plate. It only affects the throttle plate’s opening speed. It does not affect the fuel curve, timing curve or any other sensors on the motorcycle, thereby allowing any type of fuel management or flash programming to work as desired. In other words, any diagnostic or ECM tuning work done before the installation of Throttlepak will not be affected.Throttlepak’s Patent Pending technology distinguishes itself from common programming modules because it functions dynamically, constantly making adjustments based on reading the quickness with which you twist the throttle grip. Competitor products use only linear tables that can provide the rider only a pre-determined amount of throttle response.
Throttlepak’s “smart” technology senses your throttle movement, moment-by-moment, adding the right amount of assist to deliver the responsiveness you’re asking for. For example, when you want the throttle to open quickly, such as when changing lanes or merging onto a highway, the throttle response will be crisp. On the other hand, if you’re navigating an unstable road surface, like a dirty or slippery road, the throttle response will be more moderate, where you won’t have to worry about the throttle becoming “jumpy” or “jerky”.
I purchased Thottlepak prior to Fullsac Stage I. Prior to installing Thottlepak, I noticed a distinct lag when compared to my 2003 Fatboy. Thottlepak resolved that issue.