Alright i just tested you can't die in a car and gunfire doesn't damage it and if your car blows up with you in it you survive
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You can die from prop explosions such as gas stations and propane tanks!
You can't die from your car exploding with your near it!
So you are most likely completely invincible from everything cept falling and getting hit by a vehicle and prop explosions!
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[Edited by BagelBoy, 12/10/2008 3:27:26 PM]
just set physics effect high, it can kill the object by sending them to sky or hit the wall. I modded desert eagle and yet it seems to that your character have no effect by the physics effect.