Knowing what truck you have will make a difference. However, I will tell you that if you have an '08 or newer GM extended cab truck, be very careful if you plan to lower it. I had a highly recommended, well experienced shop lower mine (7" front/5" rear). It looked much better (still too high from the factory for my tastes) and drove fine. After a couple of years though, that stock large diameter, extremely thin wall aluminum driveshaft blew apart. The dealer said that it had been rubbing on the frame. I never had it off road and very seldom haul anything, still they would not repair it, much less warranty it. It does have a smaller diameter, steel driveshaft now though.
Dennis W. Parks
Author of automotive how-to books