All reputible alarm systems are going to have a starter kill built in. When the alarm goes off it doesnt allow power to pass through the starter wire. Some douchebag that doesn't know what he/she is doing and just out to screw with people probably wouldn't be able to bypass it, at least very quickly. You can put mini piezo sirens inside the car that go off with the alarm. So, if anyone thinks that eliminating the main siren would leave them in the clear they would definately be wrong and pissed. A big part of an alarm is the installation. I have sen some jobs where you can look up under the dash and see all of the alarm components. Thats not good! Also, many shopos use T-taps for quickness when installing. All you have to do is pull real hard and the connections come loose.

I know it has been stated that people do not like annoying alarm systems but they really can help you out. If you were to get a 2-way remote, depending on the brand, they will notify you of all activities with the car. Whether the hood was opened, the door, the shock sensor, etc. it will beep you on a pager or on the remote and let you know. If the alarm happenes o have a rem. start feature it will tell you if the vehicle has been started.

I think that a nice alarm and some sort of hidden switch either to the batt or fuel would be very deterring. Just becareful who all knows about the switch and everything.