Starting in 2014 GM decided to add an extra degree of difficulty in figuring out which parts were needed to lower the front of their Silverado & Sierra 1500's. If it's a 2WD then it's easy, they use the same knuckles as the 2007-13 trucks. But if it's a 4WD then things get tricky. You need to look at the lower control arm, it will be either aluminum, forged steel or stamped steel. Once you know that we can figure out which ones you will need. There are also coils available for the 2WD trucks or you can use struts on the 2WD or the 4WD trucks. On a side note, we have heard of complaints of the Stabilitac activating on turns after changing the suspension height on Sierra Denali models with the 6.2 l engine. Don't say we didn't warn you.
The rear of these trucks is basically unchanged from the 2007 to 13 models. Use shackles for 2 inches, shackles and remove the block for 3 inches and a flip kit for 4 to 7 inches.