I have standard radio/tape player and would like to change to radio/CD player in a 2001 CLK320 W208 I have the in-boot CD six disc changer and the Bose speaker upgrade system set up. There seem to be a fair number of potential units on Ebay or via breakers. What is the best way to go about it? Presumably there will be some codes unique to the units for anti-theft. Any ideas or tips much appreciated.