nowadays, duplicating car keys aint as easy as going to the Mr Mint or something like that and voila. Modern keys have tiny microchips embedded in the key itself... the sensors inside the keyhole of yr car picks up the signal from the chip, varifies whether it is the correct one then it will allow you to start yr car or open the door. Usually require coding of such keys with the manufacturer's diagnostic tester or system to match with the car.
As for your Mercs infra-red key... if you can afford a Merc, you should be aware of the cost of advanced technology found inside and along with the car.
