I had a pioneer unit on the 300E and worked and looked pretty good, but have had Blaupunkts on other cars and they worked great too. For the MB's I think some Blaupunkts looks better since some of their designs are square and not too flashy; also some economical units have iether similar back lighting color or it is selectable. This makes your whole interior have the same glow at night. I don't know if this is true with the new models but its worth a try.

my $0.02