Does it help nope! Dodge and Cummins guys did a great job with the OEM air intake, pulls cold air from the front of the truck through the inner fender and into the air box. But if you add supporting mods to your truck a bigger air box/inlet/filter can be used. Supporting mods would include: bigger injector nozzles, larger or twin turbo setups, programmer, straight through exhaust, beefed up tranny...list goes on and on....been there done that my 2005 had plenty of mods, at 517hp and 1200ftlb torque and got great fuel mileage, I did it not to get the fuel mileage but for some extra hp and cause I had nothing else to spend money on at the time!
If you want to help that Cummins do the straight through exhaust, safest mod of any.
