This time, pay some money for an alarm system. It sounds like you will spend a decent amount of money on some other modifications, but why not go for the security system as well. Sure, a dead bolted door is good, but they could just break the window and completely get around the issue. Also, why so much on the stereo? If you feel as if it may get stolen, then don't go crazy next time. Decent head unit and speakers. I know you like to listen to music, but it doesn't have to be of the best quality...
Also, was this done while the car was parked at your home or office or just on the street? (It sounds like at home). If you have a garage, use it!
I'm sure there will be much more useful posts, but I figured I would throw my two cents in...
