Excellent kit one of the best upgrades I have ever done on my LLY improved throttle response lower EGTS completely changed the tone of the exhaust much deeper rich turbo whistle sounds like a jet engine now. I have yet to dino the truck after I have installed this kit but I can fell a huge difference in power so I'm sure the numbers will be substantial. The kit included everything needed to install from start to finish all gaskets all new bolts for the manifold and up pipes, this is a must as half of the original bolts break during removal. what I liked most about this kit was both manifolds are pre-drilled and tapped for EGT sensor with reinforced bosses this is actually the reason for replacing my original set up I had drilled and tape my original manifolds 6 months ago which had caused a crack to slowly form and got worse day by day to were my truck became undrivable. I strongly recommend this kit to anyone looking to make more power from there Duramax. kit has been installed 3 months now and all components are still holding up well.