I have recently bought a 62 plate C4 Picasso which I am quite enjoying in a relaxing way!
While it is much newer and higher spec than any car I've ever owned before, there is a glaring omission - the stereo doesn't do bluetooth and I'd like to play music and make phonecalls.
The stereo in it is, I believe, an RD4. Comme ca:

FWIW, the central info screens have a bluetooth option, however it is greyed out.
From some research, it seems I have a couple of options.
1. add a little bluetooth transceiver to the cigarette lighter and tune the radio to it.
2. add a piggyback bluetooth module into the wiring harness. Something like this: https://www.ebay.co.uk/itm/174258438840
3. get a second hand RD45 stereo and install that.
Some questions:
1 - cheap, but won't display anything on the info screens
2 - seems simple, cheap and discreet. Will it display caller ID/track listings on the screens?
3 - Is this straight swap? Or does it need "coding"?
I know there is another option of adding a bluetooth/aux module in the glovebox (currently absent) but that just seems like 2 but more hassle?
Any thoughts?