Seriously, I heard those cars were made before MB decided to do something about corrosion. Every one I have ever seen had rust, including the Southern cars. In the window seal channels, in fenderwells, on rockers and rear trailing arms, hinge pivots, front frame members, etc. etc.
W116s also end up with ugly, deflated, and collapsed rear seats.
However they are better than w123s as far as drivers' cars go and I would be thoroughly delighted to find one in nice shape, i.e. no rust. I could deal with any other issue but rust. The interior layout is very nice. Really beautiful cars.
Scrutinize the vehicle with a magnifying glass for rust. Look everywhere.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)