It looks like you may be getting hooked on Mercs... A potentially expensive addiction. The timing chain seems to be a pretty common consumable on a lot of MBs. I’ve got a couple of 450SLCs and they need their chains (and guides) replaced about every 100000km to be safe. About the same as timing belts, which are a LOT easier.
The US delivered 380SLs came with a single row chain. So bad, compared with a double row, that I think it was a factory recall to upgrade it.
One of your early posters said E was for economy. Not sure if he was tongue-in-cheek, but E is for Einspritzmotor, meaning fuel injected engine.
By the way, they all look pretty nice cars.