Believe me, you do not just download the PhysX branch and change the collision behaviour, unless you are a really experienced coder with experience in that area.
Implementing collision ‘freak out’ algorithms, i.e. error handling the collision in PhysX is far form trivial. I work in a similar area, and have seen professional people trying. But you can always downlaod and try yourself…
Sure, PhysX handles all collisions, line traces and so on, that is clear.
As with regard to your examples: did you notice that most ‘big’ games use Havok? Guess why! Or guess how the games would behave with PhysX!