You need to leave it off. :bigthumbsup
It also pulls timing and affects other area's of the tune. You shouldn't suffer detonation but it will slow you down.Seems to me that if TCS also in addition to braking cuts the fuel that there is a risk of detonation in a situation such as a drag race where the engine is trying to rev with WOT. That is a scary thought to me. Keep it off.