Ive yet to look into it, but i know guys are hardwiring and old smartphone and setting up a GPS app and synching it to the current phone....this tells you where your car is anywhere in oz. The trick is to hide it where the would be theives cant find it.

Also, how about putting removable bollards the main exit of your garage. Theres a few guys out there that come and install them so theres no way they can get your ride out of your garage...not enough room.

Cameras are probably best used as evidence if criminal activity occurs.

...Better yet, get loyal 4 legged family member....no, not a mother in law .......my labrador might be all cuddles, but youve got bugger all chance of getting through if im not home.