I had a great idea while reading the kill switch mod write-up and I've just ordered the parts to complete it, I just thought I would share it with you all.
First of all, instead of using a momentary switch like in the write-up, I decided to go with an ON - OFF - ON switch like this one from Mouser.com, and here's why.
First, position 1 will make our green/black wire circuit to the starter relay, which will start the truck.
Position 2 (OFF) will break this circuit entirely, thus the ignition will fail to start the truck.
Position 3 (which is my favorite) will redirect the 12v power coming from the ignition switch to a piezoelectric driver like this one, which will be hidden under the dash.
So, if someone were to attempt to start my truck with the killswitch in the ON position for the driver, not only will the truck not start, but their eardrums will be battered with 180db of screeching in-cabin siren for the duration that they attempt to turn the key.
SO, not only will they not be able to drive off with my truck, I think their nerves will be shot enough that they won't even notice me waiting outside with my Mossberg as they exit my vehicle.
(Will post pictures when I complete the mod).