I'm fairly new to the W123 world, having purchased my 280CE in January. Since then, I've been really searching for ways to upgrade the sound. As you know, the stock speaker locations can be very challenging.

After months of searching for a solution, I finally found these:

https://www.blam-audio.com/en/lfr80/

BLAM is a fairly new company started by the primary engineer behind Focal with the intent of making 'the French sound" more affordable. Bad name, great speakers. The BLAM LFR80 is a 3-inch, full-range driver that is small enough to fit in the stock front dash location and sits low enough that the stock grilles can be used. The installer made a small adapter for the speaker, but there was absolutely no cutting or modification of the car. These speakers are crazy-good and not just for their size. I highly recommend them.

I currently have a JL MicroSub (Single 6W3v3 MicroSub) in the rear passenger floorboard powered by a small Kenwood KAC-M3001 amp mounted under the dash. This is temporary until I can find a long-term solution.

As for the head unit, I have a Kenwood KMM-X704. It may be ugly, but it powers those speakers fairly well and it has built-in DSP. Even with the most basic settings, I was able to make the speakers "disappear".

I have sent the original Becker Europa off to be modified with the Aurora Design FMR-2.8. It will look completely original, but it'll have Bluetooth, HD Radio, AM, FM, Digital Amps and Preamp Outputs.

Ultimately, I want to have the highest sound quality without any visible modifications without spending more on the sound system than I paid for the car.