"IF" you don't like how soft and far the suspension falls. I've personally found it better to put a lower add a leaf in the main spring pack.
I did this most recently on my GM 1500 using a Zone brand product from American Truck. $50 shipped to my door. Made my rear 3900 lb suspension, 2 mileage main pack with lower overload, a 3-1 setup. I went from a 3-4" drop with my equipment trailer, to a 1-2" drop. Truck stays level vs being tail down.
This leaf also may to will raise your rear end. My case about 1.5". A bit more than I wanted by it self. I also replaced the front struts with a leveling set that raise the front 2".
At the end of the day, my truck still has stock rear high look. But front and rear are stiffer, I can carry more wieght without the truck sagging as much. I am about 2-2.5" overall taller with the spring lifts and an inch diam taller wider tires.
A WD would be cheaper and easier if you don't like the rear sag you currently have. As noted by at least one other, you really don't need to do anything to safely tow your trailer.
Marty
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
2014 Chevy 1500 Dual cab 4x4
92 Red-e-haul 12K equipment trailer