500 is usually maximum I get from my N/A impreza... But its hard to say, because I rarelly get as low as light trigger, usually when I am 25-50% tank I top up.
What I do know however, best consumption I had was on highway, within one day, at morning took full tank, at evening I was refilling and application was showing 8l/100km which I consider big success. I did few 200km/h pulls tho(if I remember correctly it was two, rest was in 120-140kmh).
if I go combined, country roads and town, I am at 10-11, and Dublin only 12.