Northstar didnt get DOD. dont expect great mpgs. I think i remember hearing they geared the Bonnie GXP funny for some reason and it hurt mpgs. My STS got 16 around town, 18 if i was very easy on it. On long freeway trips i would see mid to upper 20's. Of course the STS had the 5spd auto, the Bonneville will have the 4spd