Rear wheel liner GTS style left 928.504.303.04 They cost about 400 euro each
Rear wheel liner GTS style right 928.504.304.04 They cost about 400 euro each
Finally newly made original Porsche Liners as sold by Roger Tyson, 928SRUS.com.
The rear fender has funny washers to attach the liner to the holding bracket. here's a picture:
This is a wheel arch lining made by Lokari in Germany