I own one of these in .40S&W
and I'm buying one of these this summer (for carrying) .380auto
Laws in New Jersey are ridiculous. However I can walk around with a cannon on my hip in Florida... cant wait to move. Here's how I see it, in order for him to attempt to get my car from me, he'll have to threaten me. I assume all threats to be life threatening and therefore I can defend my life. I train as often as I can in different situations, moving / stationary / speed loading / distance accuracy (15-25 yds pistol) / and speed draw (tactical, not western or gangster junk).
I do agree with whoever said that excessive force is possible. IE shooting them as they're running away, however. If he's in my car trying to take it... I'll be reloading an empty gun. I'm not proud of it, nor will it be something to brag about, but especially if I'm with someone, I have a responsibility to keep them safe.
There's a difference between Killing and Murder. A guilty man murders, an innocent man kills. If you don't make that decision either you'll be murdered or he'll go on to hurt someone who couldn't defend themselves. Your spouse, mother, sister, neighbor, or friend.
I'll probably catch some flak however, figured I'd represent the other half that wont walk away from what they worked hard for knowing insurance will reimburse them.