Efficient ways of making a car unstealable?

[Jack91]

Hi all.
So I live in a pretty rough neighbourhood, break ins and thefts happen pretty much every night. Cars are starting to get stolen often aswell. Sometimes older ones, but lately a lot of new, even high end cars are getting stolen. Every night I block in the girlfriends new car, and puel the fuel pump relay out of the ute. I figure Ill hear it cranking and catch someone. Is there any better way though to secure a car through a series of kill switches?

I was thinking a hidden on-on switch with off in the middle. Push it the right way and it enables the fuel pump relay, push it the wrong way and it latches the horn on until you turn the key to ACC. I would like to back this up by a momentary push button inline with the starter solenoid. Would I be wasting my time? Anyone got better ideas? Apparently steering locks are pointless.