When i bought my 230sl it had a terrible black radio in the dash. In addition the opening had been made to take the 2" DIN radio (which meant they got rid of the bottom dash trim as well!).
I have read all the threads re Becker radios - trying to work out what to do, but it seemed that even if I spent the money and got the correct radio and welded up the dash there would be a chance I would not be happy with the volume or sound.
Seeing Garry's 280sl with a radio delete plate made me realise how good the clean option of the plate was. I got a delete plate from Germany and used it to make a slightly larger one out of 3mm bevelled aluminium - relocating the badge to the made up plate. It looks great and one day - when I'm welding/restoring the car I will get it back to original.
To overcome the music I got a 'motorcycle amp' off eBay for about $20.00 delivered and wired it up to the existing speakers, painting it matt black and putting it loosly in the console. You are able to plug in an MP3 player (like an iPod) and the sound is great . If I don't want it seen I simply put it under one of the parcel shelves.
Just thought I would share my solution as someone may have a similar dilemma.
Also if anyone has a dash trim I'm in the market!
Richard Rose