dude get some type of alarm for it are you nuts !!!
go on ebay and get a cheap one ($50 ebay) mount it behind the glove box or hide it good if it has a lock/unlock feature (and your car has factory remote) use that to put a starter kill in if it don't have one.
buy one of these
www.ebay.comand put it in side the car maybe two of em. make it so bad that as soon as the door is open it will go off and with a few of them (I have one on the out side of my car they are loud and will drive you nuts ) screaming might work what do you have to lose
a buddy of mine put an alarm in his car (broken in several times ) with a pager he didn't install the siren or the led so when they broke in he knew and they didn't well people got hurt/arrested and it wasn't him
