I am having internet difficulties, so I will see how it goes.
I think it is important for me to give everyone an idea of my background, so they can better determine how and why I came to various conclusions. I have had several trucks and slide-in truck campers since 1972. I have installed/used various spring setups, including overload spring packs. I have a very strong mechanical background, with a pretty fair education and rarely hire someone to work on my equipment, and then only is special equipment is required.
Tires - I think this is typically the single most important thing in how your truck handles. Due to expense, tires are usually the last thing addressed. I will ignore the load capacity issues for this discussion, and simply state the softer the sidewall, the greater the flex/squirming of the tire. Most people believe this to be sway. In my opinion and experience it is not sway, and can only be solved with a stiffer sidewall.
Anti-Sway Bar - As the name implies, it eliminates or reduces sway. It has no other function. The larger the bar, the greater the reduction of sway.
Shock Absorbers - Again, I will say, as the name implies, they are intended to absorb shock. They typically play a very small part in reducing sway, and have nothing to do with supporting the load. They have a major role in reducing porpoising, which is related to the truck wheelbase and the concrete slabs at a given speed. This is where incab controllers can be very helpful.
Airbags - They can impact several things on your truck. Simply stated, they carry weight. The best install is individual air valves. The deluxe install would be individual air valves with an in-cab controller. If over inflated, can cause sway. They work with your spring setup, and are not intended to replace the springs. They can be used with most spring setups. Because they are adjustable, they can be used with or without a load on the truck. My primary use is to bring the rear of the truck back to its normal height with the camper loaded. I use the bags to level the truck side to side, especially while camping. Forget to air them down without the camper, and the truck will feel as though it has no rear springs. I have had the same bags since about 2002, with no bag failure. I have damaged both upper mounting brackets hitting speed bumps at too high of a speed.
Springs - Lots of options here depending on your use of the truck, how it was equipper and what you want for a finished ride. I will not go into all of the available add-ons, and will simply say my springs were stock (no overloads) for about seven years. I added a leaf, and am not happy with the change with an empty truck.
Each of the things above will be a little different on each truck, and overall weight. They are all designed to work together. The only regret I have with my suspension is the extra leaf I added to the spring pack. A very small improvement loaded, but too stiff with an empty truck. Regardless of your configuration, I encourage you to keep an open mind, identify what it is you do not like in your trucks road manors, and solve one issue at a time. I am convinced that an anti-sway bar and airbags will always be my first suspension upgrades. Depending on my tire load capacity, the tires could be moved to the top of the list.
Wayne