****!! It depends on how you drive it too, if you drive it hard you will not return much more than 20 mpg if that, conservatively you could get 25+ also the condition of the engine would play a role. Some mustangs are like bmw M5's if you drive it hard you get 22mpg if you drive it 'normally' you get 25mpg so why not drive it hard all the time! A good place to find out all out american cars especially the mustangs is the speed TV fourms www.speedtv.com its an american site and most of the people on there have vast experience with mustangs so you can find out all the real world figures from owners on there.