Re: This is probably very bad..
"Merc build quality took a shocking nosedive after the daimler-chrysler merger and hasn't recovered since the split."
If it had been only build quality, it would be relatively easy to improve. But most problems started with design flaws, supply chain havoc and general pennypinching. Pretty much like Opel/Vauxhall screwed up in early nineties. Lately, it's been improving again, but it may take yet another design generation to get it right.
Anyhow, last good Merc was W124 - which was phased out in 1995, three years before D-C merger. Much-lambasted W210 was introduced in 1992.