Oil Cooler Fan Series Resistor
The original mounting hardware: M6 x 20 (actually 22 mm long) hex head bolt and a M6 flanged nut.
Porsche now (July 2013) calls for:
900 378 030 01, a hex-head screw M6 x 20,
N 011 524 27, a 6 mm flat washer,
N 022 148 12, a M6 lock nut.
The problem is, the bolt is now a flanged hex-head which does not fit into the cavity of the series resistor. Of course the fasteners could be installed in reverse order; nut on top and bolt coming through the bottom.