This is great news for everyone. I doubt there is any difference in the ECU's from build dates up until this point. It would be a good guess to say that Japan may already have this information and begin installing "corrected" ECU's for the US STi's.
I don't know if I need a "fix" or not being just over 700 miles and no WOT just yet. The recommended fuel is available in this area, but for those in 91 octane parts of the country this is excellent news for them and their pistons!
Hopefully someone will compare the fix to the non-fix ECU on a dyno so *we* know what's affected.