Aftermarket Fuel Rail

gen3 fuel rails flow alot better than the gen2 ones, not sure if they "need" upgrading. 
 
you could always try and find either a rail of an gen3 NA or gen4 3sgte. they're both top feed.

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.

ID2000's cost me just shy of $800 for 4.  ID1000's are much cheaper I believe.
 
Just fabbed my fuel rail for my car yesterday, looks like a good thing.  Opted to encorporate the standard plastic isolators on the caldina head.  Assume they are there to assist in keeping heat out of the rail.

What do you guys think of the Wolfkatz fuel rail?
And will the injector dynamic fit into the Wolfkatz

I also went with the RacerX rail and id2000 

What mods do you have, power goals?
 
You shouldn't need any more than a Walbro 450

I suspect you will be fine, the only thing I was concerned with was the end of the rail itself which turned out to be a non issue anyway. Mind you mine was a gen3 head so not sure if there's any "special" differences there that'd cause issues, but considering most of the after market parts available are for gen 2 (at least anything that is different between gen2/3 will generally specify which one ) I'd be guessing you're safe with it.