Who was the guy that ended up in his car upside down at the bottom of a cliff?
Don't think you could get out if the car was on it's roof.
Obviously, this is something to be avoided anyway. 
You don't need to open the door to get out of a turned-turtle VX. The doors on mine were against rocks on the drivers side, and exit through the passenger side window (the one visible in this pic – lhd don't forget) with the door closed was my route – the door top was blocked against rocks too.
Wasn't much space, as you can see – helps to be fairly trim if you want to emulate this trick

, but when you can smell petrol and you're trapped under the car, you are unusually motivated to get the fcuk out of it!
So, Lambo-style doors would not have made any difference.
Sorry about the pic quality – the garage took this when they recovered the car.
Edited by speedyK, 17 February 2006 - 01:05 AM.