Im no expert but my unit should fit as becker is the Mercedes standard .. since there was another brand of stereo connected to the speakers .. their connectors may no longer exist so the speaker wires may have to be spliced together.. but again the overall dimensions of the slot for the head unit should allow for a pretty good fit.. and the changer can be mounted anywhere you like.. I had it in the trunck of my 300sdl with plenty of cable to spare.. so it should fit .. you usually have to take out the ashtray to get the present head unit out... and I had to take out my back seat to run the cable for the changer there were just a couple of screws and a release lever on each side of the seat..Im not sure about the SL though
good luck

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