I replaced the factory 30 gallon tank on my 2010 with a 47 gallon aluminum tank from Transfer Flow Inc. out of Chico CA. Transfer Flow carries tanks for both gas and diesel. My particular configuration (short bed) left me with 47 gallon max tank capacity under the bed of the truck. It cost me $1300 complete and I love it. The only problem you may have is that CA has to test and certify their tanks and that takes time. As a result I had to wait until November 2010 to get my tank.