cams and cam gears would be a great mod....really spread out your powerband
i've seen the kinetix intake manifold in person and i can tell you it is beautiful...definitely worth picking up....plus it has great gains
also if you don't have an safc-II that might not be a bad idea to pick one up and get it tuned
as for suspension....i wouldn't go with the Teins personally...there are so many other companies that make a much better coilover than Tein for the Z33
may want to also consider a brake upgrade
as for the wing.....i like the nismo wing personally....think the car needs the rest of the kit for that monster wing to look right