I'd like to start shooting like a cowboy. However, the fact is that by shooting, you are probably more likely to injure or kill someone as the person driving your car. I would only advise shooting if the person was recklessly driving the car and he was an immenent threat to innocent bystanders and/or yourself. If he just came to jack the car and flee, I suggest that you immediately report the carjacking to the police. They will get the car soon enough. Plus, there won't be bullet holes all through it.