I had to replace the whole gizmo on my W124 a few months ago.
Great pics man!
This valve is used in other MBs, and in other MB applications, so the cones are just vacuum "shunts", for lack of a better word.
They are part of the switchover valve and I had to procure the entire unit from the dealer ($116 I think).
Phil at FastLane printed up a diagram for me to identify the part, but alas, he didn't have it in stock.
Bring the old part along if you plan to replace it...I had a tough time telling the parts guy here what I was referring to.
I would also contend from Gilly's comments that I got no improvement in performance as a result of the replacement.
But I'm chasing down vacuum problems, so everything vacuum-wise was getting replaced if it needed it.