Did you try to reset your throttle before you guys race....this car learns your habits and adjusts to it so if you feel a lag before it kicks in it could be that and for a quick fix you can reset your throttle,,,there is a post on here somewhere on how to do it.
http://www.mbworld.org/forums/showth...56#post1725156
Also most who puchased the sprint booster says it solves the lag problem permanently