Yeah I just saw a video on that. They are staked in, while mostly everybody (maybe only US vehicles) else in the free world uses retainer clips in theirs to hold them in which my chevy had. They make it so the universal is actually serviceable. What it looks like is BMW sets the universal in and then they press the opening to form tabs that hold the universal in. To remove you would have to grind off the tabs which ends up being way more work than the average joe would be willing to do, plus you would have to be able to re-create the tabs.
Someone has to make them, where do the guys doing the remaned ones get their parts? One solution would be
http://rockforddriveline.com/replacem.htm, however I didn't see a direct fit for our vehicles and the only other you tube video of someone using this brand showed they snapped it off trying to do a burn out.
Or you would need to machine new grooves to hold the ring and probably bore the holes to use a universal that would work....yeah that is not worth the trouble.
But for the extra $160 at this point, it would be worth it just to have it done.
WDE46 - yeah I just checked the link MarkusMarkus posted, that one doesn't come with the guibo.
No idea why BMW just couldn't use serviceable universals that could have been removed.