Hi Roger
Mercedes should not be a problem. You may need an adapter from the old radio cable to the DAB cable. (I used one for an old Subaru).
Antenna is included, possibly an extension, depending on where you mount it.
Microphone is also included.
Greetings Ueli

Needed an adapter cable for my car. Toyota Jg.2000. Micro and dab cable are included. Important: Mount Dab antenna according to instructions, as more stations can be received this way. + Activate dab socket in settings. Old FM cable can also be plugged in. Yes cable is needed for function, but is included. Micro cable is 3 m long. My colleague has mounted the microphone on the speedometer, I have it on the rear-view mirror. Works