The MSRP from the MB accesssory catalog for the changer (99 model) is $746. The parts people told that included the installation kit.
The dealer charges $1000 for it installed. Being the trouble maker that I am, I told this to the mechanic who installs them. He was not very happy that the dealership is collecting $254 from which he gets $15.
My point is that the dealer may bot refuse to program the system to find the changer but I'd find out have much it would cost before I bought and installed the changer.