Here the E46, you can see the inside of the external CDV, all it does is reduce a large bore to a tiny one. So the part that was removed here .. I agree, it looks like a duck. The small diameter even looks the same. Zeckhausen's page doesn't show the inner bore.
At 2:40 you can see the bore pretty well
I really want that to be out .. I don't think I'm going to be able to leave it alone for much longer. Now that I fully understand it I can feel it working [against me] all the time.
newtis.info has the factory procedure for replacing the slave, but it isn't very interesting beyond what's already been discussed here. The recommended grease is "unirex s2" .. which is a little hard to come by. So, "Any good synthetic grease will work great for throwout bearings and spline shafts. I use Bel Ray synthetic grease. Autozone supplies them." Subaru used a red grease, which didn't last 60k miles and turned to a horrible squeaking noise .. inside the bellhousing on the pivot ball, so drop the trans, just to grease a nob. sold..
The 'pentosin DOT 4' is also at advanced autozone. It would be great to see the E9x part side by side.