If you cannot get a DPF Delete then you are screwed on fuel mileage. Mine was getting 10-12 unloaded and when I pulled my 16,000# fiver I could get anywhere between 5-7. The fuel mileage on the 450 is really bad, especially if it has the 4.88 rearend gear. I have since deleted the DPF and now I am seeing 13-15 unloaded and I have not pulled the fiver yet with it so I do not know how that will be.