Well, since the update of the engine, I am having this problem with the car physics. Are anyone else having this?
I tried with every beta that came out and the problem is sitll there. With the version 6.31.4 from before the update I don't have that problem. It look like the car has that "Mad Cow Disease".

2 Vídeos from the last BETA with the problem, v6.40.3:



Vídeo from before the update without the problem, v6.31.4:
http://s15.putfile.com/videos/c6-34012591643.wmv