If all it does is step up voltage, a simple circuit could be used to shift the amplitude up a little bit. I have all the electronic test equipment necessary to test one. When I buy my A2, I will do this:

1. Use Multimeter and O-Scope to determine what the car's input into sprintbooster is.
2. Do the same on the sprintbooster's output.
3. Compare.

Has anyone else done this?

Oh, I'm not an Electrical Engineer or anything. I'm a Ground Radar Systems technician for the Air Force. I can "view" what the input and output signals are and determine, electrically, what a sprintbooster does to change the output to the throttle.