It's also a fairly loose power guide mate. A turbo to suite 500hp is vey different to 700hp. Eg. Gt35 wod be best for your 500hp goal, but won't do a whole lot more very comfortably. T04z will get you 600hp at the wheels, but will be a fair bit more lag compared to a gt35. And still, a t04z won't get you to 700hp. The engine build involved is the same for those targets, but the different turbos will make for a completely different car to drive. If it were me I'd stick to 500hp as I still like a little bit of response.
Nitto oil pump would b my choice as well. Heaps of praise around the forums for them.
I think te bigger factor rather then what pistons and rods you choose is how well it's put together.
Is this car for street or track?