8 gallon bladdered and baffled cell. I wouldn't use foam as I've heard too many stories of it breaking down, so I went with alltech baffles from zukizzy on pirate. If you rock crawling hard enough, rocks can and will get in places you'd never guess they would. That's why I'm glad mine is a plastic cell in a steel case. Somehow at werock I put a dent in one of the corners of it, just big enough to let me know it could be done. I would also highly suggest shut off valves as well. Don't be cheap on safety and have to watch your investment burn to the ground.
With the Zuk 1.3L I would average 5 gallons a weekend. With the SC3800 I average 12 gallons a weekend. I just top it back off every morning while everyone else is tinkering getting ready.