OVERKILL
$100 Site Donor 2021
That, honestly I have no idea and do not know. CRUISE
I DO have to run the idea of trying the other ECU past the guy, it has been expressed to me "It may not work at all," it was also said on here "For $60 try and see."
It was suggested, by myself, to get a hold of Subaru specialty shop who should be able to advise you on that. Have you not done that yet? Seems like a very basic and very easy first step in getting that resolved.