Apparently according to Jake Raby, the inner seals on his bearings are leak free:
which ims bearing upgrade
I would assume with a high quality bearing the seals will be better than the OE porsche ones, but i need to do more research, perhaps combined with a freeze plug in the ims shaft to block thermal expansion and contraction the grease would remain intact.
This post does a good job explaining how oil will get sucked into the tube, though I'm not sure I agree with his solution.
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/the-frugal-mechanic-meets-a-porsche-boxster/120457/page2/
Scroll about halfway down, look for a wall of text.
Silber