I went to vegas twice since i got my car and i got 24mpg on the first trip (all highway) averaged between 3 tanks there and back but after getting offroad x-pipe and catback and cold air the second trip i averaged 30mpg (all highway averaged between 3 tanks again). I noticed that i get better milage if im cruising at 70 in 4th gear than in 5th gear too. Im very happy with the overal mpg on my stang tho. I usually average about 17mpg on the street and freeway mixed when normally going about my week.