Ok let me edit myself. Firstly I've figured out that RSM stands for Rev/speed meter (very proud of myself too :P ) secondly I found the install guide on the Apexi site. Thirdly, it does not help me at all in my quest to figure out what the 24th pin on the 31P connection does. I've got a Corolla and a Motec ECU to play with, a predecessor left a wiring diagram behind which seems to conflict itself by saying that pin 24 is either the +12V power supply to the injectors or something called 0CV+ Cam timing control. I am most confused by this. I would greatly appreciate it if some kind soul could enlighten me.