I have a 2009 2500 4x4 6speed auto with just 2k miles and recently deleted the dpf, unplugged the egr and loaded the smarty jr programmer. What a difference, I have a 4" mbrp mufflerless exhaust and the truck sounds great, not too loud and with the improved throttle response and 3 to 4 mpg increase, it was well worth it. The best thing is I can return the truck to stock in about 2 hours without a trace. I pull an open car trailer a few times a year and with the programmer on tow mode the truck didn't know the loaded trailer was behind it. These trucks are awesome.