Yes, the ESP system can and will save your A$$. First time on the track at Buttonwillow it was raining. It was my first time on any track so, according to the instructor, this was a really good thing as I'd get to learn wet track driving right away.

In the 'Star Mazda' turn I started pushing down the accelerator too soon and started to pull the rear end around to the drivers side and almost immediately the ESP kicked in and started poping the brakes individually to stop the slide... It was very interesting to feel the car save itself from a nasty slide into the dirt.

I leave it on all the time, but I may take it off on the track when I get my skill level higher.

Cheers!