On the topic of car theft:
One of the regulars at Paragon has a system in his rig called Ravelco. It's a little pin system that you can yank out of the car when it's parked or if it's jacked. The pins make connections in various systems of the vehicle, and if the pins are removed, key systems cease to function. Sounds interesting, though I haven't looked into it.
http://www.ravelco.com/