THis isn't strictly factual, but not speculation - just a reminder for the folks who are getting a touch panicky about this all....
If you'll recall, a few years ago Ford had a little car called the Mustang Cobra that had a little intake restriction problem, which resulted in power figures about 15 hp below what was advertised. There was a huge legal flap over it, a class-action lawsuit, and an "intake swap" program that Ford imlemented to fix the problem and get the power back to where it should have been.
Now, do you really think Subaru would make the same mistake? The power numbers are what got a lot of us in the door on these STi's. To turn around and drop the numbers would be tantamount to false advertising, which is what caused the row with Ford.
I'm not worried, myself. But then, I have access to 93-octane gas, and I've only gotten the detonation when I've had low-octane fuel in it. Of the 5 tanks of gas I've had, only one has been fully 93-octane, and I don't recall the detonation.
As for road trips, however, remember that this is generally only happening at WOT. Isn't that right? If so, solution: keep your foot out of it a bit until you can get to some decent fuel, or use the toluene solution. Home Depot's gotta carry it, and they're everywhere.
Just a couple of thoughts, FWIW.