found oil in the sparkplug well on my 2004 Z and in looking over the web I've seen varying comments on non-oem valve covers. I wanted to know what your luck was on replacement covers and should I just bite the bullet and buy Nissan?

Nissan definitely recommends you replace with OEM. We do have them at a discount price. At

partsfornissans.com

Gasket 13270-8J102 $15.03
Gasket 13270-8J112 $16.16
Valve Cover 13264-AM600 $224.83
Valve Cover 13264-Am610 $224.83

A friend of mine has a V35 coupe which is pretty similar to the 350, both had the same issue with the oil seeping in the sparkplug well.

I bought all OEM Nissan and he bought Aftermarket.(valve covers & gaskets) The OEM Genuine is definitely recommended and the way to go, so far haven't had any problems yet and no breaches of oil have been found in any of the wells (clocked in about 12,000 miles since install)..unfortunately I can't say the same about the other car. Aftermarket parts are hit or miss, they can work just fine or take an absolute crap sooner rather than later.

The aftermarkets tend to be made a bit more cheap and can warp from all that crazy heat thus starting leaks again.

Can't go wrong with OEM.