been there, done that, don't reccomend it. though I do feel pretty tough now.
mine was a combination of things. poor rear end set-up, tyres not so good, pushing hard, some oil on track. fast, 4th gear corner. lost it at 140km or so, came off the track backwards, slid a long way, then backed it into the wall. damaged bumper, reo, exhaust and pride. it reinforced in me the fact that anytime you are on the track something can go wrong. especially when you are entering corners at such high speed. BUT I was back out 2 days later after checking the car over.