Others have posted both a kit of parts to replace a stolen cat and various anti-theft solutions. If you search the Mk 1 section, you will find the information you are looking for. My car is garaged, so I am not at such a risk, but if I have to leave it, I plug my dashcam into a separate power pack and leave the camera running hoping that if it is stolen, I might catch an image of the ba$tard$ that stole it. I also have a cheap 3rd party cat on my car, and they are not worth much to the thief.