I have just placed an Optima (redtop) battery into my '92 W124 300E- - no fittment problems whatsoever.
Factory hold down= perfect
Fits into factory metal tray and occupies about 75% of the tray.
Positive and Negative leads and cables perfect length- no unnecessary sloppy slack in the cables
Male terminals fit into female cables perfectly.
Believe it or not, I have factory originale 1994 MB battery in 124.036 (42.9k)
In my E320 Coupe (109k), the original MB battery was replaced 2 years ago with a Sears International Gold, It too fitted perfectly.