Re: Power increases
Honestly the SyTys tend to work best if you follow the community's time honored recipies for parts combinations. If you don't follow those, you're totally on your own and bound to run into annoying problems, such as problems people dont have solutions for, or combinations that don't run right and have poor performance, and nobody has a chip ready on the shelf for it.
There's a post somewhere on here about SyTy Combinations in MS Excel format that's a good guide. For someone with the heads and cam, they would typically be a very advanced SyTy enthusiast with a few years of experience learning the nuances of tuning one of these trucks and keeping it in top running condition. They would have a PTE 50-series turbo or larger, Delphi/PTE-brand (I think?) 50# injectors specifically (not all 50# injectors are the same), and then the "Ultimate Chip for Vortec Heads/Cam and 50# Injectors" could be used and expected to provide a good baseline tune for you to start from.
An extremely stout tranny with a 2600-3000+ stall would also be necessary at these levels. If this is all foreign to you, you may be pretty new and I'd suggest spending a lot of time learning and reading and researching, and talking to members on here, before you make your next purchase or steps. These trucks are very challenging to get performance out of, and that's if you follow the "easy, well-known route"!!
Depending on the quality of the tune, and the boost being run (this will be your biggest factor), the truck could run anywhere from 14 seconds to solid 10 seconds. You'll likely find yourself start in the middle somewhere and have the potential to bring it down as you dial it in according to your skill level (or bank account).
Good luck,