I have the gen tube and crown from ofrei. I purchased them for my 45.5 PO. to my surprise they will not fit the rep case, the gen tube has thread so screws to the case, the rep tube does not have a thread and it goes in by pushing.
the Gen crown is thinner on the inside, so i s the gen tube. the only person that i know has installed a Gen Crown and Tube is The Zigmeister. I wish that he post a how to or tutorial of how he made the part fit.
Good luck