I know that recently the fuel prices have come down a little, but I am still looking for fuel options. I have looked into bio diesel and veggie oil and am still working on getting set up to make my own. I have recently been looking at adding or building a natural gas injection system. I have heard the same things with this as with all other mods like, it is cheaper to run, gets better mileage, and you've heard the rest. Has anyone tried this or know where to start?