okay i searched thread and everything but i can find the answer to this

do i need a manual transmission wiring harness(engine and tranny harness are seperate) to swap a S14 spec SR20DET in?
because i have a 1998 240sx and its automatic and my friend says i will need that manual wiring harness to complete the auto to manual swap because the computers are different for the cars and i will need the 1998 spec 240sx manual wiring harness to be able to do the auto-manual swap. hes not sure either but i want to make sure before i go to a shop and find out my car cant be completed because im missin that part.
could i use older 240sx manual wiring harnesses? or do i really need the 1998 spec one?