Do what Mike said. Changing stuff like MBT on a car that has long tubes and a flex tune is wild. Definitely doing too much. If the car isn't boosted...
Tuning can be complicated. There's a lot to learn, and it takes a LOT of time to learn it. Pay someone if your don't want to spend the time tinkering...
I Have An 07 Gen III 5.3 With 862 Heads. It Has A Truck Norris Cam, 560 Springs, Push Rods, And BTR LS7 Lifters? Is There A Base Tune Or A Tune That...