I have a dealer installed alarm system, and it works very well. It senses shock, and triggers an alarm if someone were to hit it, or break the window or something like that. It will also tell you if it was sent off while you were gone with the light on the dash. It also kills power to the starter while it is armed, and best of all it works with your existing key fobs.
I highly recommend a good quality alarm system, and installing JimmiJammers. These go in the door and prevent prying under the handle which gains access to the lock rods, and from breaking out the lock itself (I have these both installed, because I live in Los Angeles, and the crime here is F'ING ridiculous). Sorry about the home invasion, I hate thieves and Vandals with a passion!!!! Here is the JimmiJammers website..
Vehicle Security and Theft Prevention Devices