I think I found the solution to the erratic volume levels in our Benzos. I have a 2003 CLK55 that I am installing a complete sound system, but I am keeping the factory Bose Comand head unit. I too had dealer turn off the speed sensitive volume adjustment; however, Bose systems also have Audiopilot which incorporates a tiny microphone in the headliner (right of the rear view mirror, completely hidden underneath the material) that permits the system to adjust volume according to interior noise levels. This device for some may be great; however, for me I thought I was imagining volume changes in my car constantly. Thus, I disconnected the mic and have since regained my sanity. The instructions are located on MBworld.org forum under a search for "audiopilot." I really appreciate all those on the forum who did all the tedious leg work. Hopefully this helps those with similar car audio dilusions.