On a side note a question of my own, why isn't it possible to just press the old "non" replaceable uni out and install a new one, and once installed fix in place via pressing using a star shaped jig (or similar) to secure the new uni? (the main problem I can see is centering the uni?)
You can, but it costs $UBER
I had my driveshaft rebuilt a few months back.
$200 to replace all uni's and rebalance.
If they weren't replaceable (as I was warned they may not be), then the price would have gone out to $800 or so, as it would all have to be machined.