Over the past few years I have replaced 4 or 5 door cables on my 1.1 454.Mostly from ebay, around £10,. After lasted one broke, I got one from Mercedes £20. But the quality is so so much better.
as i always say, buy cheap buy twice. its worth the extra to buy a new cable from Mercedes over spurious non gen ones.
Also need the best as door slammer, feet on dash and rip car doors open: wife, :)