I was thinking about running one on my pulling truck to. After thinking about it some I think size will matter alot. If you get a large one, like you are thinking, you get alot more weight when its full. If you go with one thats small you save on weight but you may need a fuel cooler to keep the fuel from overheating when it returns to the cell. I want to get the tank out from under my truck to make me feel safer. What about material? Aluminum or one of the cheap plastic ones?