I hope you are aware that the immobiliser is in the instrument panel and you will need to get a new key/keys to start the vehicle. You will need to go to an Audi dealer for that.
Also the mileage will be different and you will need to either increase the mileage to the same as your car has done and/or inform VOSA for MOT purposes.[/QUOTE
He won't need new keys at all, just his keys need to be paired up with his new clocks, I may be able to assist if your willing to travel??