....whats good is self-created items adding to specific %s. Such as crushing blow and open wounds, thats one % you want quite high in order to severely injure other players. Freezing your opponents helps too if you can, and plenty of psn damage.
There are plenty of people that know how to do this, the thing is, as with closed bnet hacking, good things are kept quiet.
As for invincible, its never quite possible, sure, you can be invincible against some, but others make chars designed to kill you. And sure, physical immunity is possible, but can be easily defeated.
The key is to experiment, and play legit alot to, what you learn playing legit is extremely useful info when hacking.