i'm swapping my dead 25, for a fresh 25 at the moment.
and im not the most mechanically minded of people either
admittedly its taken me a while (i've been lazy as i have a company car, and rarely drive my skyline...)
but its not as hard as you think..
remove all the intercooler piping, radiator, etc etc..
unbolt air con and p/s pumps, take out radiator, remove all the wiring loom, heater hoses, fuel lines, exhaust, remove driveshaft, unbolt engine and gearbox mounts, and its essentially out.