PET Metric sizing..how to decode..
I think it is an approximation of US SMS (Sheet-metal screw) sizing, but I would get the proper fasteners from Porsche or your favorite parts purveyor.
Also check "Bel-Metric", large selection of metric fasteners, e.g. here for speed-nuts:
http://www.belmetric.com/metric-speed-nuts-c-3_856/
And this page for metric-sized loose-washer sheet metal screws:
http://www.belmetric.com/loose-washer-metric-screws-c-10_125/


