Talk to a recovery(repo) guy, they know all the tricks to get to a vehicle fast and quiet.
For all the others a steering wheel/foot brake lock, remote controlled security system with blinking light in the cab to tell you/them it is armed and a short range security/theft system to tell you if the doors are opened or truck moved. Slow them down and make them noticed.
Then be sure you have the proper personal equipment to deliver
SHOCK,AWE and PERSONAL INJURY to the bastards while you/they are waiting for the law to arrive.
I speak from personal experience.
