I replaced the foam on all 4 grills, got a set of Rainbow W124 speakers & a Blaupunkt Bamberg 470 head unit pretty much as soon as I got my 280E. With a discrete vent mounted phone cradle & iPhone cable routed thru the dash it doesn't detract from the classic look & is all the modernity you need. If you're going to do a speaker swap, see if you can source the Rainbow's (seems like they are still floating around NOS etc) they're not heavy on bass as to be expected, but the mids & highs are exceptional given the form factor & basic head-unit, 4 speakers set-up. I'm perfectly happy & see no need for anything more substantial. I say that as someone who had worked in concert production for 30 yrs.
A couple of side issues. When I replaced my evaporator a few years back, I fully expected to have to remove the steering wheel but found I did not have to. It didn't cause me any grief, particularly since I had to go the extra mile and remove the HVAC box. With regard to the speaker grille trim, I broke one of the clips on the RH side. Amazingly, it was still available from MB. (probably NLA now!) When it arrived from Melbourne, the part description on the packet was "ledge". Odd description of it but there it is....
