My 2011 Ram Longhorn Hemi gets 13.6-14 city, 20.5-21 highway. Drop in K/N filter. Truck was born with cold air induction, no need to buy one.
My son-in-law put a catback daul exhaust on his 2011 Longhorn, his MPG stayed the same as mine, but he did gain a ticket for excessive noise.
I drive 70-75 on the highway, 25-45 city. Maybe its the clean Montana air or alttude.