from my experiance it was the exact same. me, 99 4runner no s/c, my buddy 2000 4runner s/c same lift, same size tires.
we topped off at the same place, ran the same trail, I basicly followed him the whole day, got back into town and topped off again, we both filled up the same exact gallons.
BUT,, IF I had a s/c, my fuel use, would go up, Id always be ion it, lol