Well the following toys are going into the head
-1mm O/S valves (undercut, dished, friction welded, friction coated)
-Jun Titanium retainers, Viton stem seals, Phosphor guides
-MR-S Shimless lifters,
-Adjustable cam gears,
-Head porting, combustion chamber and blueprinting
-Thermal coated Jun intake manifold (with a thermally insulated gasket)
-Replace greddy sidemount with Water/Air setup
-Water/methanol injection, for safety reasons
-Borg Warner Aerworks turbo, running anything up to 30psi
-Custom exhaust manifold and downpipe
-Vband Clamp's everywhere
-Nitrous Anti-lag system (i haven't yet started this but plan on doing it, so to get a flat torque level as opposed to a torque curve, won't be stressing the engine beyond that which it will already by capable of without the giggle gas.)
Already running $15k in the bottom end, which pulled 150rwkw on 4psi on the stock head
I haven't yet got the flow numbers for the head (so i can size up a turbo and cams) then it will be down to how much the Wolf ECU can squeeze out.
I'm aiming for 500-600hp so expecting i might need as you describe, epic injectors (if it ends up being 600hp and i'm running 850cc's then fuel rail pressure will be dangerously high). I've been looking at injector dynamics (modified bosch injectors), apparently they are able to handle large flow(even running their 1000cc injectors will require a higher rail pressure for 600hp ) and a quality idle, but they are expensive injectors. As they are top feed only, i was looking at aftermarket rails. I have only been using the online resources for sizing injectors, so am not too sure how accuate they actually are.