eclispegs2008

im getting ready to help a friend with a s14 sr blacktop into a s14, and after researching i think i want to do a rb25det for myself. Anyways, i've top a ton of research, have tons of wiring diagram, pinouts ect now. These plugs though, f3 f4 m6(x)and so that need to be re-wired. What and where are they exactly and what do they have to do with the blue ecu plug, anything? What theory behind it to, rewire the engine side to the body/ecu side or is it the other way around? Finally whats kouki and zenkie (or whatever the other one is) Im new to the nissan game, been in the honda game for a while and thinking of kicking my 600whp h22 (h2b) civic build to the can for this