Here's mine, a Sierra AT Crew w/6.5". Bought it new 3rd of July 2013, now almost at 22 000 kms. Enjoyed every one of them.
Wheels are XD813 (20", tires are 275/60/20). Its leveled using RC 2.5" kit. I added air bags and wireless controller to help with my work trailer.sag.
I know the truck is uber dirty, That's next on the to do list!
Sure! They install exactly the same as the 07-13 models. I mounted the compressor and valve on the inner fender of the driver side. Works flawlessly, Bye bye saggy ass end.