Becker radio wires

I have a Becker Grand Prix radio that needs to be replaced. I have found a used replacment Becker Grand Prix from a 90+ 300E. I also have heard that the wiring on all Mercedes cars for the radio is a little different after 89 because it has a extra feature that will leave the radio on until a door is opened. MY CAR IS A 86' 420 SEL, WILL A NEWER STYLE RADIO PLUG IN PERFECTLY TO MY EXISTING WIRING ??? WHAT YEAR DID THE BECKERS GET CODES INSTEAD OF BATTERYS ???

The best radio that will "bolt" in with-out changing every thing is the 1990 model radio. The radio from 1991-1993 cars is a 2 piece radio & won't work w/out a lot of creative work. 1990 & later uses ## codes. Battery back-up was in 1986 & 87 radios.

Thanks for your post. What did the Becker GP use in 88 and 89 if the batterys were only in 86 and 87 ??? Also, what about the feature that would leave the radio on until a door was opened ??? My car doesn't have this and I don't want to run into any problems with the wiring. Thanks again

The 90+ radios were designed so that when stopping at a red light & shuting the engine off (mandatory in some euro countries) you could still hear the radio for approx. 5 sec until the key was recycled. There isn't any wiring change as the radio was modified.
The 1988 & 89 radios used a diode that held enough power to keep the memory; just like a computer when it's unplugged.