Sprintbooster: it is an inline thingy that attaches to the electronics at the gas pedal. It remaps the car to have a steeper curve. basically, when you mash the gas 10%, it replicates a 20% punch. It makes the car more responsive at the low throttle edge. When you mash it to 50%, the mapping is at 100%, so there is no more increase from there on. I do NOT recommend it on a 55K car as we have a touchy enough low end as it is.
If you floor the car anyway, then do not get it. if you want the car to be peppier at the low throttle input phases, get it.