[Dominik]

Hi Peter,
you probably progressed well now solving this problem. CV joints are "off the shelf" parts, from i.e. GKN.

I found that the ones I use on my cars are from a 2.0 Jetta FWD (same as Porsche 911). Price range from €35 to €350, each.

There is a youtube vid showing how people polish the 911 parts before installing. Well worth in a heavy duty application.