I am NOT affiliated with Pacbrake or ANY vendor selling these brake kits. I have personally had the PRKB on my 2007, 5.9 and it has been one of the best add-ons I have done for my truck. I just happened to be on their web site today and saw the rebate offer of $250 on a PRXB kit. Just passing it on.
http://pacbrake.com/wp-content/uploads/PRXB250.pdf
http://pacbrake.com/wp-content/uploads/PRXB250.pdf