For my recent E320 stick conversion using a 1988 300E 5 spd. trans (single mass flywheel) it was easy. Rock Auto provided the LUK kit you referenced below. Parts in the LUK box were Sachs products. It was about $255 in late 2016. It's currently out of stock. They list a Sacks kit, also out of stock.

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Hanno
'79 6.9 Sold (after 27 years)
'83 280SL, 5 spd.
'94 E320 Sdn. 5 spd conversion
'02 E320 Sdn.(on loan to mom!)
'87 300E (5 spd. conversion) Sold
'05 E500 Wagon