I love my 07 6.7 cummins. I get 23-24 empty on the freeway. 16 towing my 24' enclosed. Not sure if you have emissions testing where you live but the best thing you can do to the newer cummins is to find a programmer that will allow you to delete the DPF and the EGR system. Your motor will be a much happier engine and give you much better power and mileage. I really like the newer auto as well. Mine is a 6 speed and with the the factory exhaust brake makes driving it so nice and braking a ease..