Just sitting here pondering I know the lwb have 37 gallon tanks is it could be swapped out for the smaller tank so you wouldnt have to fill up as often. I searched and could not find any threads on it.
No. If you look under the truck, you will see there is nowhere near sufficient room for a 37 Gallon tank on a SWB Titan. It has been looked at a couple times when it first came out. I have not seen a custom made tank added under the bed so far.