yeah dual wheel conversions wont increase capacity other than spreading the load out over 4 rear tires instead of 2, but they also help reduce trailer sway by giving you wider track and more contact patch in rear. I feel about same as Dmax I would probably sell or trade in current truck for one witht he higher weight capacity if you really need it, a trip to local scales while towing your "normal" heaviest load will tell you if you are within your specs already or not. no sense in trading up if your current truck is already more than you need.