[tamathumper]

+1 on the VarioCam solenoid - the o-ring on it is very thin and easily torn when the cam cover is messed with, and the paper gasket is also thin and delicate. Make sure to grease the new ones up a bit if you change them out, that will help them survive the process.

Leaking spark plug o-rings would hopefully leak down into the hole, not up onto the top of the cover, but if you remove the fuel rail cover (the part with the word PORSCHE on it), you can pop all the spark plug boots and have a peek.