Hi Mark,

I new to the Benz scene, but here are some ideas from my 2002 days.

Some people would mount 6" rounds in the fascia under the rear seat. You have to cut the metal, but they are almost invisible. I put a pair of 6x9s in the rear hat tray on my car, then covered the whole tray in black speaker cloth. Again, the cutting was not ideal, but with the cloth (which looked correct) you could not see the speakers unless you got right to the window and looked for them.

There was a post on an e28 board about a guy who put a computer subwoofer under the rear seat. They run on DC and have a volume control on a long cord so you could adjust the bass right from the driver's seat. He claimed it gave good bass and of course nobody knew it was there. Or you can try a small bass tube under there.

You can get some small (unequalized) amps that should fit under the rear seat, too. They should not get too hot so cooling should not be an issue.

Cambridge SoundWorks sells a 5 speaker unit for computers that might work. The cubes are really small, about 2x2x3. You could easily conceal them under the dash and somewhere in the back if you don't want to cut any metal. (They could be mounted with velcro and easily removed if need be.)

Another idea I've had is leaving the stock radio for show while mounting a modern one under the dash. I think you could fabricate a hinged bracket that would fold up under the dash when not in use and just drop down when you want hi-fi. there was plenty of room under there on a 2002 for this setup. I don't know (yet) if it will work on one of these cars.

Good luck,

Peter