So it starts. I've had my since 02/03, since then i put on about 90k miles. I just recently got my spark plugs changed at R&D Factory, cool people btw (http://www.rndfactory.com/). They noticed a crap load of oil over my plugs, especially the 6th one. Turns out my valve cover grommets are not keeping the oil where it should be, and unfortunately they are integrated into the valve cover itself! Point being, if there are any new Z owners thinking of doing some mods, make sure to check this out first. I attached some of the pics they took, you can see how it got to the point where the plug extractor got covered in oil.

 

just had my passenger side valve cover replaced, easily a $200 part, it was leaking oil on the bell housing

 

common problem, if you catch it soon enough you just have to replace the gasket. Continous wear will cause the cover replacement also. More labor intensive than anything, whole top side of the block has to come apart. Parts are cheap considering it can run you several hundred climbing towards a thousand to replace a valve gasket cover.