You would have to change your map every time you get out of your car, and every time you get into it. I'm paranoid enough to where I've thought about doing this, but that would be such a pain. Plus I have a V1 AP, so it takes me like 7 or 8 minutes to reflash. No way.
I'd say one of the easiest things to do is tap a fuel pump wire and run a hidden whip to a kill switch anywhere you want. Glove box, under your seat, ash tray. This wouldn't prevent it from being stolen, but it won't make it far. That's been my plan for a while.
Before you worry about any of this stuff, I'd upgrade the alarm. I spent $600, and I got a clifford alarm with a backup siren and a glass break sensor. The backup siren is awesome because it senses if the power is diconnected from the alarm, and it runs on an internal battery. Supposedly that flashing LED is most effective deterant. Most guys would rather jack a car without any strings attatched.
Another great theft deterant for your stero: Glue razor blades around the inside of the stero compartment. My mom knew a guy that had his stereo ripped off 3 times in like a couple months. He did this little DIY and Viola! He came out to a pool of blood and a half removed stero the next week.
355 awhp fp green six speed wagon in Corvette Atomic Orange