well one of my points is that you dont need forged pistons or different rods to make 700 hp from an rb 26 that is a proven fact you need turbo / 's to suit and a fuel system
cams you can reprogram the r32 gtr ecu or you can fit a plug in power fc or what ever ecu you like.
take for example an rb 26 for sale fully rebuilt stock pistons 272 cams balance, ecu etc 7500 turbo /'s to suit 3-4k injectors 1 k cooler 1500 ,fuel pumps 600 add 2k for things forgotten am I close?