Depends what you want to do, really.
That's what I'm doing, supercharging:
1. GTM SC Stage 1 kit (including better fuel pump, injectors, fuel return system)
2. Full true dual exhaust - ARK + ARK test pipes
3. Gearbox cooler
4. Oil cooler
5. Stainless steel brake lines + Motul 660 fluid + Ferodo DS2500 pads
optional 6. Better suspension package - KW V3 coilovers, Eibach ARBs, SPL drop links, SPL front and rear camber arms
optional 7. GTR intake + GTM fuel rails + GTM adaptor to 370z
If you want to do twin turbo:
1. GTM MHI TT kit, available soon-ish
2 - 7 as above
8. Valve body upgrade - GTM
9. Torque converter upgrade - GTM
On both situations you need UpRev licence and remap / dyno time.
No modified bonnet required, but I have the Seibon CF bonnet with vents, helps the cooling a bit.
P.S.
Follow my thread here, have a browse through: http://www.350z-uk.com/topic/73768-never-posted-in-the-370z-area-before/