That kit looks solid, but it is pricey. I just watched a video on YouTube for this kit, but on the previous generation silverado. They had to drill the knuckle out 1/2" to get the ball joint to go in. It doesn't seem too hard of a job. What size tires are you looking to run?
After more searching on the forum, i found this:
http://www.gm-trucks.com/forums/topic/156839-assist-steps-running-boards-nerf-bars/page-28?hl=%20running%20%20boards
Post #420
His older ones worked on his 2014.
revivng an old thread, but does anyone know if the 2014 running boards for a crew cab fit my 2008 crew cab? I found a cheap set, but want to see if anyone has had any luck using them?