More secure...

Okay, I was talking with someone yesterday who mentioned a specific number of Escalades that have been in stolen in my area. I'm not sure if I believe it, but has me thinking hard!! As secure as my truck is, I want to add some more security, so i'm brainstorming more ideas. A question I have is... when someone gets into your truck, how do they get it started? Hotwire it? Considering they get by my aftermarket alarms, is there ways of stopping them from just pulling down a few wires and leaving with my truck?