David, that is for sure.
That's the funny thing, if I had VSA or DSC or whatever the heck they want to call it, I would probably run a few runs at auto-x with it on and then a few with it off. To try it. Most people just turn it off.
A lot of the systems do kill power though, some just kill power completely which stops any type of wheel spin, resulting in slower time in any type of competition. Not that wheel spin is good, but if the driver notices it he lets off the throttle a bit, if the computer does (in some of the applications) it kill the engine and it takes another 1-2 seconds before power is regained.