I don't have the S2 but have the S1. This thing is exceptionally good There is a "push you in the back of your seat sensation" in first gear and I surprised the heck out of a 2003-5 M3 today from a standing start. There is so much wonderful potential in this set-up. I can't imagine not trying at least the S1.
2012 535xi M-Sport, Carbon Black, Cinnamon-Alum Hex, Exec Pack, Tech Pack, HUD, Damper Control, BMW Apps, Heated Rear Seats