Whichever rig you decide to go with, a chip will help immensly if you don't pull a load all of the time. Simply adjust it to perform the task at hand. As stated oil changes for diesel will cost considerably more, but you dont do them at the same intervals either. My dad has the old 7.3 ford diesel (2002) and chipped was getting 4-5 mpg more than my 1/2 gas chevy (2006). Of course when he loaded the 4 horses up and quick tuned it, we were getting the same. lol