Done an egr bypass and dpf delete with a smarty jr. Programmer on my friends 6.7. Mileage increased about 5mpg unloaded. No problems outta tha truck since then, its been about 2 years since. But if you're gunna mod it any I would suggest in a aftermarket clutch assembly., even with just the jr. It'll smoke the clutch. I worked at a dodge dealership for a couple years, never had real issues with them unless it was driver error, like using dyed fuel in it, pulling fuel out of a drag up tank with out a fuel filter and clogging the injectors, running high ash oil like rotella t in it and destroying the engine. All that being said the cost for the egr bypass, dpf delete, and smarty jr. Was around 1300 or 1400 bucks. And with any knowledge, some hand tools and a weekend in the shop you and your buds could do it no problem. Hope that helps man.