I've heard that a shift kit can really wake your truck up and help fix some small problems as well. It makes your shifts a little quicker and firmer. The Transgo HD2 kit is generally considered one of the best for our trucks and they run about $80 for the kit itself. You can install it yourself if you are careful and patient and the Transgo website even has an installation video. To have it installed by a shop runs about $250 total I think