For those of you using Mobil One, I would recommend the extended performance version. It uses an ester base similar to Redline, Royal Purple, Castrol Edge and Amsoil. The regular Mobil One uses an organic base (this is the oil that Castrol Edge compares itself to in their commercials stating that it offers eight times more protection).

Mobil 1 FTW:

Mobil 1 Selected as Factory and Service Fill Motor Oil for New Nissan GT-R Multi-Performance Supercar

If it's good enough for the GT-R, should be good enough for the Z.

^After doing some more research on esters, it seems like there may be some real needed benefits that the Nissan Ester Oil brings to the VVEL system (esp. in the long term). And what's more, since we don't know exactly what esters are in the oil, you can't just go out and buy a Group V synthetic ester oil and hope it does the same thing. So, until I find out EXACTLY what is in the oil I am probably just going to stick to using the Nissan Ester Oil instead of Mobil 1, or any other synthetic for that matter.