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