Not "very cheap fuel" it is free fuel so yes there is a huge difference, at least to me when I commute 45 miles a day each way to work and have to drive 75 miles each way to pick up and drop off my kids regularly. I also would like to take some trips this summer with my FJ40 on the trailer behind me so I can go crawl some new areas so this makes the trip 100x more affordable.

Basically it alleviates any need to worry if the 5 gallons left will get me where I need to go as long as I have the oil tank filled.

In fact I am planning to modifiy one of the Dodge kits for my FJ40 and switch it over to a 4bt. This way I will run a 5 gallon fuel cell with diesel and a 15 gallon cell with waste oil and I can go crawl all day for free.

See where this is going? My hobbies revolve around cars and driving and I don't want to nor am I ever planning on giving them up until I die. I will convert everything I own to run on diesel if I have to in order to keep doing it.