That 27/39 must be Imperial gallons. Is that realistic?
This long weekend we drove the Forester to Calgary, spent two days fighting Calgary traffic, drove home and then drove in the city here before filling. (yes, I got gas in the meantime...)
Anyway, the Forester averaged 8.2L/100kms for the trip, including city and highway. Highway 2 is not a great "mileage" route thanks to the relatively high speed, but at least you can maintain a reasonably constant speed and there are no hills, curves, or anything interesting whatsoever.
In normal city driving, we get 9.5L-10.0L/100kms pretty consistently.
So, in a combination we got 34.5mp-Imperial-g. Considering the gridlock in Calgary we hit, that's durned good.
In all-city driving, we get 28-29 miles per Imperial Gallon.
So, I don't see those estimates being all that far off. Sure, drive like a maniac with a lead reight foot, and that 2.5L will eat gas, but other than a Smart, what won't if you mash it all the time?