Like some others, I went for the best range I've had regularly which is 551-600km. I've probably seen 600+ though can't remember for certain.
My car is a 2004 TL AWD without any engine mods.
Figures are for country driving obviously and although economy for AWD isn't as good as a FWD the difference is probably more noticeable for city driving. My economy for country driving is fine by my account.
For city driving I get 12-15 L/100km, maybe more in pure stop-start traffic. That would equate to 400-500 km if filling up at 60L. (How much do you people push the last few litres of fuel in your tank?)
For a few months I was working in Canberra and living in Sydney. I could do the whole return trip on one tank. Specifically that was Sydney northern suburbs - Symonston - Tuggeranong - Symonston - Sydney with four cold starts.
The best economy I've seen on my trip computer over a significant distance was when filling up in Sutton Forest on the Hume Highway when the engine was warm, restting my computer, and heading (downhill!) to Sydney, a distance of more than 100km, with around 8 L/100km showing.