This is one of the nicest W114s I've seen in many years:
https://www.carbids.com.au/c/allbids-car-auctions/classic-unique-sports/12-1970-mercedes-benz-230-w114-4d-sedan-cream-23-1528787
Looks like original plates and still has the AWA radio that would have been dealer fitted.
Did an upgrade to the Radio over the weekend. Even though I can't put a slimline radio in, at least I can use the knobs from one.
https://www.classicjalopy.com/2024/03/w111-becker-grand-prix-stereo/
I managed to get a good used pulley and have it installed, so the car is back on the road.
I also learned something about the car I never knew. It has a coolant/oil heat exchanger.
https://www.classicjalopy.com/2024/03/m129-heat-exchanger/
I think it depends on how much they are used. If the car is in constant use and getting regular fresh fuel, then I you probably don't need to clean. But once it sits, after a few years the tank probably needs to come out.