I finally printed this base and what shall I say....It's fantastic!
Got two of these fans https://www.arctic.ac/de_en/arctic-f12-tc.html
I can't hear anything from the control box any more and it stays much cooler than with the old stock fans.
None of the old fans is inside anymore and I took the power for the new fans directly from the powery supply of the box.
Thanks a lot for this base!!!!