What's the best physical car security device around?

My daughter has just bought a new BMW 2 Series Convertible which has to be parked on our drive. What device would you recommend she could attach to the steering wheel for extra security?

What's a good front and rear dash cam?

Is the Apachie front/rear dash cam a decent product and at £35 with a 16GB memory card do you think it's value for money?

Can I connect my iPhone to the Bluetooth in my 2007 car?

I have just bought a 2007 Mercedes-Benz CLK. Do you know if its possible to connect my iPhone through the Bluetooth ?