Get whatever security system you like, if you have a flashy car, something bad is bound to happen. And living in Socal...multiply that by a few.

Anyway, I would just get a decent alarm system and get it installed by someone who knows what the heck they are doing. If they are going to put the brain under the steering wheel, chances are it can get disabled pretty quickly. Find an installer who is willing to take more time and hid the box. And along with that, install a couple switches. Switches merely interrupt the circuit of a component until it is turned on.

And last of all, be smart. Know where to and not to park your car. Know when to and not when to park your car.