The date on that article is 2005

Funny that they are talking about GPS tracking. I actually have a GPS/GSM tracker on my desk at the moment, it's designed to be fitted to a car, and reports its position to either a phone via SMS or a computer via GPRS. It's a little bit bigger than a pack of cigarettes.
A better solution would be to include a receiver so that you can text message your vehicle with a special code to disable it every time you leave the vehicle. If the car has a GPS system, why not be able to ping it for its location without alerting the thief?
I'm trying to work out what the command is to trigger the tracker's output so it can be used to shut the car down. The manual they provide with these is written in engrish.