Reindexing Tbars won't do anything for ride. unless you were bottoming out before or you have them cranked to where you're on the bumpstops for down travel. Regardless of where they're indexed, the ride quality will be the same because the spring rate doesn't change...they still settle to where they're going to settle with the weight of the truck on them. As long as where they sit is in the operating range of the suspension, you're fine where you are.
As for the pop, get under the truck and crank down those 4 bolts on the front most cross member. Popping from there is pretty common. See if it goes away. Otherwise, another set of hubs should be easy enough to find, and reman'd axles are under $100 and can be replaced in about 30 minutes.