I am about to finalize an order with Mark Dodge, however, I am wondering if there is a way to determine payload based on configurations. I am seeing very different numbers for the same vehicle when using the ramtrucks site to view a vehicle that is currently available vs. the Ram look up my vehicle site vs. some dealer's websites. Even the specs of nearly similarly configured 3500s on the ramtrucks site show payloads that very widely. For example, one Laramie 3500 Limited Longhorn Mega Cab Dually with HO engine shows a payload of 3990 pounds on ramtrucks but 5340 pounds on look up my vehicle. Another similar Laramie 3500 Limited Longhorn Mega Cab Dually with the standard diesel shows payload of 5,520 pounds on ramtrucks and 5,340 on look up my vehicle. After we looked at a Mega Cab today, my wife and daughters are set on that cab, so I need to make sure I can max payload to tow a large 5th wheel. The other towing/weight specs are all fine.