that depends a lot on what oil you use. fuel filters do add to the cost a fair bit. but overall i get so much better mileage it still ends up cheaper. what 400-500whp gasser gets 17-18 mpg city? i dont even know what i get highway but its got to be +23.

depends what your doing with the truck. once you start puting go fast goodies on the gas truck your mileage is gona suck, i can have my cake and eat it too.