Most cars has some sort of variable valve timing at least cars in the Z price range. Now if you are talking about something similar to honda's VTECH, or iVTECH, than thats a different story. Not only does vtech affect valve timing it also changes lift by engaging a larger cam profile on the exhaust and intake cam.
Nissan does have similar technology, its called VVL (it actually can activate the exhaust cam and intake cam at different rpms). This can be found on some SR series motors (sr20ve, sr16ve, sr16ve N1). Too bad its not on the VQ motors. But if you plan on boosting than it doesnt really matter.