Hmm..hard to justify a plausible self-defense, on the other hand a rock-salt loaded 12 guage does wonders. The victim will run off with a burning ass that will continue burning for 2-3 weeks Buy a good $100 wireless pressure sensor with a light indicator to tell you when someone is standing next to your car. It's clean, cheap and you wont go to jail since you wont be killing anyone with rock salt.