ok, get yourself a good alarm from DEI...I recommend a clifford intelligaurd series, probably the 8000. this sets you up wih some pretty hardcore things already, proximity zone motion sensor, tilt sensor, and all the little tid bits that everyone likes. To add on get yourself a second siren with a backup battery,this way when the schmuch cuts your batter cable he is screwed because the backup siren is triggered and he now has another siren to locate and deal with...which he probably wont do, he will run. For even more protecton add a third siren inside your car, make it a loud one 130+ dB's. I have a clifford, its ated at 140 dB's...wouldnt want to actually be in the car when it goes off. Also, put a magnetic sensor on everything that could easily be stolen..amps, box, crossovers etc. And for the ultimate inprotection...get the system that the cops use...I dont know what its called but you could do some research...once the burglar breaks nto your car and somehow triggers your syste by either settingoff the alarm with te magnetic sensors or the proximity sensors or by hot wiring your car, the doors lock, the ignition disables itself, the alarm goes off, and the windows wont roll down...basically the dude is screwed, this is where you come into play with a nice bat or in my preference a nice 9 iron...and then give the guy a swift hit to the face...garaunteed he, nor any of his punk friends will break into your car again. Good luck!