The Aveo is a decent car for the money. I had one for a while. It was a 5spd. I didn't do any advanced driving techniques with it, just doing the speed limit and avoiding brake use. It also had no modifications. My normal commute was on 55 mph roads and I got low 40 mpg most of the time, sometimes high 30 mpg.
Here is the fuel log:
http://ecomodder.com/forum/em-fuel-l...vehicleid=3955