If you haven't already replaced the upper plastic bushings I would do that first before buying adjustable lowers, my truck only has 88,000 miles and the last 10,000 it started wearing the tires badly, I just changed the upper bushings and couldn't believe how worn they were, not sure if the previos owner never greased it or that's all the longer they last but it's relatively cheap and easy to do. The 2 bushings and 2 gaskets were less than $60. 00 at the dealer. Unless you have bent your axle it really shouldn't be way out of adjustment.
Happy Rammin,
Caleb