my V8 is pretty poltert, in any case the front crossbar bearings are already flat. I haven't looked closely at the back, but at 235tkm they won't be the best anymore.
I have now seen that at au-tel.de there are the front crossbars completely for 79.- Euro, and the rear ones for 59.- Euro. In addition, there are the cathedral camps for 24.- Euro. I think it's all pretty cheap, are the parts okay? Can you buy this?
Then a few more questions about changing yourself...
1. Do you have to get out of the pendulum for the change of the cathedral camp? (I don't mean the axial groove ball bearings now, that the feather legs have to get out for that is clear). WHEN they have to get out, I'm saving myself the change...
2. I would then completely replace all the crossbars (let them be). I have a well-equipped private screwdriver on my hand, which has always helped me well with my previous Audis. But he certainly never had a V8 in the garage. Can I, in a good conscience, push the crossbars into my hand and say, "Go ahead!", or are there any special features that a "normal screwdriver" doesn't know so much? Should I give him the RLF? The car would be measured in the workshop anyway.
Are a lot of questions, I know.
But not everyone has to be answered. 
Thank you very much for information!
Ciao,
Jens