^^^^^x2^^^^^
There's an old saying that if you don't know where you are, you can't get to where you'd like to go.
Start with finding out what you've got for a suspension now.
IMO, the OEM suspension for your truck is a great suspension, so it would be great to know if you in fact have an OEM suspension, or if it has been modified. The OEM suspension is an active suspension, where the stiffness of each individual shock is adjusted automatically and continuously to match road and your driving conditions (like going around curves, applying the brakes, etc.).
Regarding sway bars, I'm sold on the Hellwig brand. They virtually eliminate body roll, and could be considered for your use, once your existing suspension is identified.