Will an 03 UK STi ECU fit a 2001 UK WRX ?
 

:wonder: Question as per the title, any help would be appreciated, thanks,
Mike

What are you trying to achieve? If you're figuring that plugging in an STi ECU will give your WRX more power, it won't, even if they're pin compatible.

Your bugeye has no AVCS and other bits the STi has...........won't work I'm afraid.

Shaun

Better of just getting your Wrx ecutek remapped ask on here who does ecutek remapes in your area