Thanks, guys. You don't make it easier on me, with the contradicting suggestions. The things is, they don't make turbo wagons (Legacy or Outback) anymore so it's really hard to find a good, low-mile example, even in the Land of Subaru, where I am. I've been looking for a couple of months now and still no luck. At dealerships you don't know much of the OCI history (the CarFax rarely shows all of them) and owners don't always keep records. This particular car has records, but there are lapses - it is not certain that they skipped those oil changes, they just don't have the records. The oil that's currently in the vehicle looks like it's been there for at least 4-5K miles (what the owners thinks it is) and the level is actually a little too high, so it seems like it hasn't been consuming oil. My 155K-mile 2.0L WRX still does not consume any oil, and I used to go over 10K miles between oil changes, using Mobil 1 (when I did 10K miles in four months).
It's so hard to decide! There is now another '08 OB XT at 59K miles, with a CarFax full of oil changes but it has four 4500-5500-mile OCI and one 7300. Did they do them but were not recorded? No way to know - it's in a dealership. Will there ever be one with pristine service record?
What about those extended warranties that you can get through Subaru dealerships? Is that any good?
Why don't people spend some money and time to maintain their vehicles properly! What to do...