I can speak only for myself and my particular car. With just under 8000 miles on my car, its ECU has been reset once, by the dealer, at 3k miles when I brought the car in for the 3k service and complained of the surging/hesitation/whateverYouWantToCallIt.
I started off using mostly Diamond Shamrock 93 octane, which gave me over 80,000 miles of surging-free driving in my turbocharged GTI. Then the service manager gave me his snake-oil spiel about TopTier and I've been using Shell VPower 93 octane, with no discernible difference.
Since it's a new, fully-warranted car and I'm the kind of schmuck who'll make the dealer fix what needs to be fixed, I haven't "monkeyed" with anything.
So, I realize you followed your list of action items up by saying this would help those of us with an actual problem to get it fixed, but you must admit that your statements made it sound like most owners who have this problem have created it themselves, which I think is a total crock. When I demonstrated the surging problem for the shop foreman last week, he thought for a moment and said that he had noticed similar behavior in a number of other turbo Legacies, and seemed pleased when he got off the phone from finding out that the Techline has a fix. There is something wrong with my car that should NOT be wrong with a $30k car from a reputable manufacturer.
I'm making no guesses about whether or not Subaru's reprogramming of the ECU will reduce or eliminate the problem I have with my car. It won't cost me anything but the 12-mile drive to the dealer and the awful torture of driving a cloth-seat, non-turbo Outback instead of my LGT Ltd for a few days... how will I survive?
Yes, this is annoying... but I've gotten more and better service from my dealer and from SoA on this one issue than I got from VW in 3 cars and 15 years. I'm going to cut SoA some slack for a while longer.
DKB