Well, first I'm going to quote from the Radio Recoding Guide that all the dealers recieved a couple weeks ago:
MY (thats Model Year) 2001 C-Class with Audio 30 Radio,
Radio anti-theft protection:
MY 2001 C-Class vehicles with Audio 30 radio incorporate
CAN-bus version coding for anti-theft protection. Radio and
code cards are no longer used.

The CAN-bus version coding in the radio must agree with that
of the vehicle in which the radio is fitted. If the coding does not agree with the corresponding message on the interior CAN, the radio switches over after about 30 seconds to the Production mode, as indicated by "PROD" displayed on the radio. In the Production mode, the radio does not react to user entries and other functionality also does not exist. Radios recieved direct from the PDCs (Parts Distribution Centers) are shipped with the radio version coding not set to model 203 and therefore will arrive in Production mode. The sequence to version code using SDS is as follows:
Control Units/D2B-COMAND or Audio/Control Unit Adaptations/Read Coding and Change if Neccesary/Version Coding/CAN Message Series/Set to "203". SDS version coding of the radio will not be neccesary after loss of battery power as the radio will retain its version coding parameters.

Models 203, 208, 210, 215 and 220 equiped with COMAND have no radio coding procedures.

(Ok, I'm back, thank you Mr. Mercedes). The way I interpret all this is that if the version coding isn't there, it's not going to work. i haven't a clue how this would go into Production mode unless the version coding isn't done. i'd be interested to see what on the interior CAN is sending out a message to the radio, which then is supposed to agree with this message and decide that it is OK to work. It just ain't happening this way. If there is no version code installed, it will be in Production mode. Once it is out of Production mode, it's going to work, or at the very least it's going to work in any 203 chassis. Funny they even do the version code, as the 203 is the only car this radio will fit. I should go into the version coding on a new car just to see if there are any options available for the chassis it will fit, maybe it also will work in a A-Class or V-class in Europe. I wanted to do a car to car swap, but could only come up with 1 203 chassis, a black C240 6-speed, very sharp, Sport model. One thing I did try is to open the drivers window and lock the car, then reached in and opened the door from the inside, which of course set off the alarm. Then while letting the alarm continue, and without inserting the smartkey into the ignition, I could still turn the radio on, so obviously this whole thing about the radio code being in a chip or something in the key must be false. If it wanted authorization from the key for the radio to work, then why would the radio work if the car was broken into? Makes no sense. Well, I've gone on long enough. I'd be interested in someone elses interpretation of all this......Gilly