I have remade about 10 or 12 shafts it’s an easy job, and you notice the difference instantly, I would say the last few that Porsche had were made 180 degrees out, ie your steering wheel ended up upside down, not a massive issue, if you have air bags disconnect the battery 20 mins before removing the steering wheel
the Bailey Morris UJ is about £30, plus fitting into the shaft, and yes they are staked in but that’s not a problem
the whine on startup is more than likely the alternator belt, the alternator is at max load just after a start, just needs tightening a bit, the manual says 10mm deflection in the middle of the belt run
only down side is you will have to take the under tray off to adjust it
let me know if you want your steering shaft rebuilt, I dont have any good exchange units at the moment, the last person never returned his knackered one to me, so I have no stock to rebuild