...search search search search search
Now that that is out of the way, I don't think we can really give any advice until we know how much power you want, N/A vs. turbo, etc.
Also, (as I think I say in any thread mentioning cams), there is a *vast* difference b/w what is streetable in a Z and what most would consider streetable. These cars are light, so they don't need much to get them going.
If you want easy power, you likely can drop a L28et head/intake/exhaust/turbo/ecu assembly right onto your engine and run it just fine. That'll run you...very little out of pocket
If you want NA power though, be prepared to spend a little more $$$ for less power.