If its an internal prox it will only go off when someone sticks their and in the car. They also sell glass break microphones that will set off the alarm if it hears glass break. Your bottom of the barrel cheapest protection. 2.4ghz wireless baby monitor under the front seat. Voice activation so you dont hear everything that goes on. Have the receiver just a few feet from where your sleeping and go lay the smack down on who ever is messing with your car. I do have an alarm, a nice dei, but the monitor was left over after my little girl got a little bigger so i decided to put it to use. If someone taps my glass i can hear it inside the house and it runs off a little battery. The razorblade thing is a little extreme.

400whp or bust.