I replaced factory tank w/ a Transfer-flow 50 gallon. No problem working underneath truck. The T-flow is made from metal while the Titan is made of plastic. Both have their advantages/disadvantages. If you go w/ T-flow, make sure you get the "undercoating" option for it. Will take a few hours to replace and a helper is good to have along w/ a floor jack and wood. Tight squeeze getting your hand on top of tank to re-attach the wires and all. Based on 9-10 mpgs towing, good for about 400 miles before needing fuel tho 10 gallons remain. Figure that's a reserve.