Sadly as said you will never beat the car thieves, you can only slow them down. If they want something, they will go to all means necessary.

ALL methods of security can be beaten. Even trackers everybody praises about can be jammed with a simple device anyone can get hold of.

So then you have the people who put bollards up, there was someone on here who used to chain their cossie to a lamppost! Even if you think you car is the most secure and unstealable, they will just kick your door in and take the keys.

Its a sad world we live in, but with the law on their side, theres not much we can do about it.