Ome of my dads friends have a 04 Cummins 6 Speed H.O. not 600 and he wants a chip that will yeild him the best fuel mileage. His fuel mileage is killing him now. My dads 03 H.O. had the edge EZ I think is the name it adds 70HP and 220TQ and got like 4-5 MPG better than stock. With 4:10s and an Auto-:t . So I wanted to know what ya'll thought.

Thanks
Nathan