I'm looking at updating from a 1999 2500 2wd to a 2006 or 2007 5. 9 2500 4wd. I have been researching some upgrades and I was leaning toward a Smarty S06 PoD, 50HP injectors, FASS, S&B Intake and Manifold, 5" Exhaust then Gauges etc. During the research I am confused about the Injectors and...