I've driven 2 different SRT's, one with a Sprint Booster (mine) and one without, back to back. There's honestly a huge difference between the two cars and how they respond on a light tap of the pedal. When you mash it it won't matter too much but for light to moderate acceleratoin it's a big difference.

I just wouldn't buy one brand new, it's kind of a lot for a little electrical piece.