Dude if your looking for turnkey performance that truck is not the way to go. They have been hopping up cummins for how many years now, and we have been playing with the Duramax for how long, 8 yrs. To me it is more impressive to make big power with a Duramax that takes some ingenuity and finesse. Than to be able to stack 2-3 boxes, exhaust, intake, turbo, etc. The cummins is a good motor, and as I hate it say is built to take more from the factory, but it still has its flaws. Just because it will hold 800 or so hp from the factory doesn't mean sh*t when that injector tip cracks and burns up a piston. Or in some case, breaks off and fubars the head and piston.
Thats just my .02 on the matter. In the end it is your life and your decisions. Who are we to tell you not to spend money. But as it has been said on this forum and many others you are still going to have to "pay to play" no matter what your driving.