I have vsync on.
But as far as can understand, you are using the c_move to detect collisions.
And as a programmer I know that you cant be 100% percent correct with c_move. Take for instance two cars that are in opposite direction, they are always showing ridiculous collision behaviour in your demo. They shouldnt be overlapping or passing through each other.
60 FPS is a good framerate and you cant blame that for bugs in your collision detection. I prefer the physics objects instead of c_move to control the collision, as they are near percfect because they take the whole geometry into consideration, and NEWTON is best for every situations.
I have projects that run at 30 FPS but dont show any kind of bugs that I see in your demos. I would like to know if my prediction is correct.