Hi, new member. I found this forum (and post) while goggling for an answer for the exact, I mean exact, same problem. I have a 02 CLK 430 and have the same issues. I thought it was the phone system so I swapped it out for the Argos system but the problem still remains. I will add this, I also have a Blackberry
Music Gate plugged in to the AUX port in the glove box and you get the exact some noise...