Some say it is the VCT Solenoid that starves for oil, it is a known S14/S15 related problem, once you start and put it in first gear it goes away, no ill effects. Sounds much like a rattle, others say it is the intake cam gear that needs replacing. Some have replaced the solenoid and the noise has disappeared and others have replaced the cam gear and it has gone away. Don't worry . Several forums have discussed this so you can search for it, on here as well.
i wouldn't stress if your vct noise goes away when the car is warm and on idle, if it only goes away when your in gear id maybe look at replacing the solenoid as the gear doesnt tend to go, though that is argued
As noted above, you could change the VVT solenoid (Variable Valve Timing), this should get rid of the noise, but i'm not sure how big a job it is to replace,maybe someone else can advise...
As for Oil, yes Fully Synth is the way to go. I'll be replacing my oil early next week and have some Silkolene Pro S 5w40 waiting to go in (replacing Pro S)