I can answer the CD changer problem. I had the "No CD Changer" problem when I took delivery of the my 99 E430. The dealer replaced the fiber optic cable and the main unit. The problem went away (kind of). The technican told me that the fiber optic cable was bend somewhere during the installation at the factory. Therefore the main unit only received signal intermittenly.
However, I still experience "No CD Changer" maybe once every two to three months. I notice that when it happens the engine always takes a "bit" little longer to start.
99 E430 Sport