That makes sense.... That definitely explains why the 5MT ECU didn't work. Thank you for that info. It sucks I'll have to take the belt off again but I guess it's not urgent. Its running fine now..
So I (my brother) discovered the problem with the high idle. Turns out when I spliced into the speedometer circuit it must've told the car that the cruise control was on. So the last time I used the cruise it was on the highway at around 3k rpm. So I just unhooked the cable that goes to the throttle body. Problem temporarily solved