PhysX is fine, stop crying. Also the liquid (oil, coolant) appearing could be like a copy&paste from Carmageddon. It doesn't have to show up in crash because it wouldn't do it anyway. Only in the aftermath when the wreck have been steady for a while. And now that I think more Carmageddon style, the wrecked cars did have to stay in place a few seconds before the oil comes out. In that game(s) it's just way too large area to be realistic, but who really cares?
