Here is how I believe it should go :
ECU ----> On the incabin plug there is a Black/White wire ( ECCS Power Relay). This wire should be connected to the Black/White wire (12V const. to ECCS relay) from the 8 pin plug near the P/S in the engine bay. So it will be Black/White (engine bay) ---TO---> Black/White (incabin).
IGN ----> I read that the Series 2 doesn't have IGN to coil relay. I traced the Black/Red wire from the ECU and I see it splits in 2 other wires 1. Gery wire that leads to the injector plug and 2. a Black/Red wire that leads to the incabin plug. Now I believe that the injectors get there power from the ECU. So I will not need the 12v IGN to coil relay wire (Thick Black/Red wire) from the engine bay plug. I read that the 12v wire should connect to the Red wire (pin 4) on the incabin plug, but I see I don't have this (think it's because I have a Series 2).
Coils ----> I found he coil plug. There are 6 wires that go to the ECU and also a a Black(ground?) and White(12V power feed?). Just like the IGN I believe the coils get power from the ECU.
If there is someone that has done a RB25 series 2 swap I really hop you can help me with this.