I have had my 6.4 for almost 3 years. While researching on the web I have decided that a DPF/Cat delete is better on your truck than the stupid regen process. I tow a 15,000 lb travel trailer at least once a month to BBQ cook-offs all over Texas. My truck has the power and I have no problem pulling it. The rest of the time it is my daily driver. With out the trailer I get around 10-11. I understand that the power increase with the tuners is one of the ways that you can get better MPGs. I have searched and read all over the web about people with tuners pulling large loads. Some love it and some hate it. The biggest complaint seems to be with the way the truck shifts and EGTs getting up there. A local shop has a Dr. Performance kit with the pipes that will just shut off the DPF for $300. He said the company went out of business and this is his last one that he wants to get rid of so that makes me a bit leery. If I decide to get a tuner (H&S, Spartan, SCT) to get the higher HPs and improved MPGs, who has the best tow program, or can I just go back to stock (with out DPF) settings when I tow? I know that everyone has a fav tuner and I know that almost everyone has asked what tuner to get and everyone has answered this question a million times. I have searched and read a lot before asking. I just like to have as much info as I can before I jump in and do something like this.