RB30 NA's dont put out 120kw;s at wheels. I had one with a few mods was lucky to push out 98kw;'s at wheels.
Im not knocking the RB30DET as im building one myself , but you cant take away the power a rb20 can make with reasonably small mods.
u can make 300hp at wheels outta them with stock injectors , ECU , and AFM.