From what I have heard, the traction control devices keep the rear wheels from spinning if you stand on the throttle coming off the turn.
I have heard that some of the ones in the legends cars are plugged in and removed by the driver. So they could remove it and put it in their pocket before they even came off the track. I have not seen one, and I wonder if a good driver couldn't beat it anyway. Throttle engagement is a feeling, and you can tell the drivers who get it just by watching them race. Seems to me that such a gismo is just doing that job for an inexperienced driver. That being said, I'm not worried about my driver getting beat by it. Sounds like a crutch for folks who aren't smart enough to learn how to setup/adjust a car.
As far as shocks go, INEX could do a shock swap and really screw up a cheater's setup.