Sorry I cant help you with the alarm, but I can suggest a kill switch in addition to it if you really want to go all out.
You could do it your self. You just need a relay and wire. You can hook it up to anything relating to starting the vechicle, but the fuel pump is a good place for it.
The fun part is hiding the switch! People have done thinks like you have to turn on the rear defroster to turn the car on, and once its running, you can turn the defroster off. I've also seen a car where you have to hold down one of the buttons for the power windows in order to start the car.
Just an idea....