I'm considering adding a wiring harness as an extra layer of security to my car. In theory how it would work is that the car and wires "X" would have female plugs and the wiring harness would be the male plug that connects it all together. I just need advice on what wires I should equip with the wiring harness? Something under the dash or inside the car. Would it be a good idea? Is this a good layer to add along with kill switches?