124, Big sound upgrade for Little money:

[Paul T]

Thanks to the replies of some members (HITMAN, and others), and some archived disertations from Chris (Zeuz) and John Elliott (see mercedesshop.com/wikka/w124audioamp, and mercedesshop.com/wikka/w124stereo?show_comments=1), I have enjoyable sound in my 1989 300E.
* Forget identical replacement speakers. The plastic surrounds that the speakers sit in are perfectly round , and outside of a Rainbow replacement, any other speaker will have some sort of mounting tabs that do not fit in the opening.
* For the front speakers, I bought a set of 4" Rockford Fosgates (MB Quart would also do) for $35 to $50 dollars. They are smaller than the opening, and are held in place by painter's latex caulk ($1.99/tube), which not only holds them but also stops the sound waves from the back side coming out.
* For the rear speakers, cut a set of 6 by 9: speakers into the rear hat shelf, possibly Infinity 9612i. I used an old set of Optimus 6x9's and got good results. The stock speakers are disconnected.
* Run new wires from the head unit to the rear speakers, bypassing the fader control.
* I was able to find, near the head unit, front speaker wires, going to the fronts from the fader. Hence, easy wiring to the front speakers.
* New head unit, Pioneer DEH 3800 (HP, MP whatever the new one is 6/2006), which has 50 watts per 4 channels, and a great tuner. More than enough power. $129 from Crutchfield.
* Everyt'ing cool, mon.