ECU for 2004 STi

Does the USDM 2004 Subaru STi have a 16-bit or 32-bit ECU?

I'm getting mixed answers,lol!

USDM MY2004 is 32 bit but with less memory space available than 05-06 so custom code availability often differs, and it has no immobilizer.

If you're talking about another vehicle market please let us know.

Nope, this helps a lot thank you.

Have you heard of running a flex fuel system for an 04 STi on open source software? Im looking at a MerpMod patch for Romraider Carberry (since the later runs at 16-bit) which is my primary question?

I'm trying to stick with open source as this is the best cost effective option for my car. I already have the FlexFuel sensor, re-purpose the TGVs, use the secondary O2 sensor bung at the end of my midpipe. I just need to find a program that will let me set the parameters, scaling, etc. for flex fuel on my car.

Carberry is for the older 16 bit ECU which is not suited to the wiring of a USDM 04 STI, or its engine/triggering.

I don't use MerpMod, can't comment on it.

For a USDM 04 STI converted to race use, Link's plug and play ECU works well, has flex fuel and much more.