It's really hard to know what's happening in the video's without knowing how you've set up the car. All of those seem to me that you've gone in just too hot, or you're running very low rear downforce. Something I had to learn very quickly with PCARS was that all the 'go faster' techniques I had learned in GT didn't work in PCARS. Whether that's realistic or not I don't know, as I have no real life racing experience. Like any racing game, once you learn it's particular 'quirks', these things happen way less and become predictable. When I started playing PCARS I was also spinning and struggling to catch the car when mishaps happened, but now I can throw cars around, induce and catch slides, while knowing what the car is doing.