Good luck finding a 5-speed to fit these cars. My impression is that even in Europe, they weren't a common option.
In a hilly, urban area, I sometimes wondered how well a 3.46 ratio from a NA 300D would've worked in my recently-sold, automatic 240D, which made such a racket at highway speed. Perhaps a 3.46 would've made that car more tolerable, without compromising performance too much.
OTOH, despite missing a hood-pad, my solid-body stickshift example, with it's factory replacement engine, is much more pleasent & relaxed at high speed. sounding more like a high-reving 4-cylinder gas engine, without that overpowering diesel roar.

Happy Motoring, Mark

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