The W203 C Class and W209 CLK class has had two different technologies used in the Audio systems, D2B in pre facelift (MY 2005) cars and MOST in post facelift cars.

The W209 CLK class, uses the same PRE facelift parts as the W209. After the facelift, the parts are completedly different.

The W463 G class also used pre facelift audio units, however the COMAND units are different and C class parts will not function if installed in G class, and if you install G class units in a C class then you will need to add extra wiring to make it work.

This document covers the pre-facelift (i.e D2B system) audio system part numbers. The post facelift documents for  the C and CLK class are different and can also be found at www.mercupgrades.com

This document shows the part numbers for the different systems - US, European and Japanese systems are all different.

Mercedes regularly updated the audio system in the W203 C class and W209 CLK class and the later part numbers in each section are the newer ones (where the entries show "replaces above"). Sometimes there are more than one part number that seems "current" for a given vehicles.

The W209 CLK class was first released for around MY2003, so the MY2002 parts in the list below were never actually fitted to the CLK.

The post facelift system can not be reasonably fitted to the pre-facelift car - many other control units in the car need updating to make this work, and its almost certainly cheaper to just buy a post facelift car !