[brucepick]

Kudos on the improved mpg! Not easy to do in an auto Subie, from what I hear.

Another low cost "mod" is increased tire pressure. Because Subies require wear-matched tires all around, I'd set the pressure equal all around. Or perhaps just a tad lower in the rear if the weight on rear wheels is substantially less than in front.

In any case, start with the tire's imprinted max. That's my suggestion.

Look up the lowest weight (thinnest) oil allowed by the Subie owner's manual. Make sure you're not using anything thicker. The only exception as I see it, would be if it's burning or leaking oil.