My car is a big turd. Best deterrant - Drive something no one would want to steal
I think a lot of these cars get stolen with a truck. I know I can hear my car start from anywhere. Fuel cut is ok. What if one of your friends is the ahole to take it. I’m sure he/she will see you flicking some other switch every time you start your car. Just sayin’
Though I Think GPS tracking is the best route. Or simply dont leave it in a spot it can be stolen. I have my car in my garage on a camera with a car blocking it in the driveway. The cam is there mostly for parts. 
THIS!
agreed!