If you want an absolute theif proof car there are bmw stereo systems which need a code to enter inorder to start the car. Then there are double locking systems. Anti tow alarms, wheels locks which engage your braking system and doesn't let go of the rotors, pagers, alarms you could hear a mile away, alarms that use subwoofers that blast absolute noise far stronger than any ear could handle and causes internal organ damage,low jacks,ect The question is: is it worth to spend to protect spending 100,000 to protect a $30,000 car.
My friends family owns 3 lamborginis one M3, M5, hummer1 and a Mclaren f1 they have a security system on there garage that locks down all windows and doors and turns on all the cars. There was one proffessional attempt to steal the cars and a team of 15 people died. That system costs nothing because the father created it him self using motors, sensors, and keyless start ups.