Thought i would share this. Additional to all the security that is advised on here.. tracker, disklok, pedal lock, ball bearings in screw heads etc we got fed up of still sleeping with an eye open all night. This was because regardless of all the security we had on our landy, and two dogs less than 10 m away they still got it and we never heard a thing. So, being a mother I came up with the idea that we need to hear these cretins as soon as possible.
We bought a standard baby monitor. One with the sender (baby's) that is also run by battery back up as well as by plug. We installed the monitor, hidden from view and attached it to the cars battery using little transformers etc. (hubby did this) we now have a visual with lights and audible warning when anyones around it. You can hear the rain dropping on its roof and even neighbors scraping snow off their drives. Its not fool proof, its not infallible but unless they have the skills of Mission Impossible they are going to struggle to break open a lock or bust a pedal lock without us hearing it. (these monitors can be very sensitive, think of trying to pick up babys breathing)THEN we can phone the police and let them know there's a burglary in progress.Also, if that monitor goes out of the receivers range, an alarm goes off. This is for mums that are in the garden and are warned they are out of range of the baby. A second warning that your landy has just moved away from the house. We have all the other stuff too, including DNA mrkers. We sleep at night now and think, if they take it, then there was nothing we could have done.