Hi guys, here's the details of the car:

99 GC8 WRX
APS Cooler, APS Intake, Z32 AFM, Silicon Intake, HKS full exhaust, PowerFC. Think that's it. It's tuned to a safe tune.

Basically, I'm trying to remove the APS intake/Z32 and PowerFC.

Naturally my issue is with the PowerFC. Something to do with the wires.
Upon removing the plugs, for some reason wires 4+5 were in use on the blue plug, instead of 5+6. This threw me off. Anyway I went ahead and tried every combination in order to get my stock ECU from working, including utilising ports 5+6 and I could not get it to work.

I get a check engine light as well as the immobilizer light on the dash is on and static.
If i plug back my powerfc, these symptoms go away (though I haven't managed to make the car start yet even when reverting - that's another issue).

A bit more background info, when I got the car, it wasn't tuned and had no powerfc, but I did get my car alarm removed and install a cyclops alarm system. Not sure if this is related with the immobilizer somehow, or maybe that is actually something to do with the wiring. Or the ECU is fried..?

Any thoughts would be great, going back to work on it tonight.

Cheers