Sorry, I don't check the E class forum too often. I usually leave that to ajcrowe and bigbenz man.
To the best of my knowledge, it is impossible to connect a cd changer with copper wire. Your car which was intended for the German market is somewhat different. It hs a different headunit. The headunit provided for cars sold in the US is not available in Europe. On the other hand, Europeans have several choices in headunits with cd player or cassette player and even a single DIN opening navigation system, the Becker Audio 30 APS. Also, all US cars come prewired for the cd changer, but the Euro cars do not.
I don't know as much about E's as I do C's but I am certain that only the two cd changers from my first post can be used in any MB built since 1999. They require the use of the D2B fiber optics ring. The change must be placed in the proper order in the ring. I don't remember what it is, but I could probably find if you need it. Eventually on of the microprocessor must be configured for the cd changer. Otherwise fault codes will accumulate until the changers stops functioning.
I ask ajcrowe or bigbenzman to move this thread to the Audio forum because I check that more often. If anyone with better knowledge of the E has different or better information, please share it with us.