I went with the Bilstein 4600. Some websites showed the 5100 would fit my truck, but then again some sites dont even ask for a submodel for me to choose if it is the SS. When I went directly to the billstein website it showed a front and rear in the 4600 but nothing in the 5100. Oh well, The 5100 was maybe a little more than I was anticipating spending. I am sure these will still be better than the generic ones from an auto parts store or the GM garage.