Permanently installed fuel tanks in the bed are just that -- permanent. I installed a tank with a hand pump that I used during our trip to Alaska. This allowed me to pump in fuel when I needed it in an emergency. When I returned home, I removed it (just had it strapped in) and I now have full use of my truck bed. If you actually use your truck for hauling other than just towing, I would think that the permanently installed tanks would be a huge PITA. I have a 16 Ford F-350. It has a 26 gallon tank. Obviously, this is a joke for a tank when you are getting 9-10 mpg. Even so, I was able to drive 10,000 miles on our Alaska trip without using the extra tank -- had it not been for being stupid and careless.