Anti-Theft Suggestions.

If a thief wants your car, the thief will get your car. Make your car less attractive and someone else's car more attractive to the thief. Club, flashing red LED on dashboard, no valuable-looking stereo or other stuff clearly visible, park it next to a more theftworthy vehicle (and under a streetlight), hidden kill switch(es)...

...or, y'know, drive a '56-'64 Chrysler product with automatic transmission. They might get it started, but they won't know how to shift into Drive!