I bought the Flashcal and upgraded it to the Flashpaq a few months ago when the update was 50% off. Anyway, the Flashpaq setting are different from the Flashcal in the arena of the Paq having pre-programmed tunes (Economy, Crawl, 87 Perf, etc.) where the Cal only does stuff like tire size, gear ratio changes, and other creature comfort adjustments, but the Paq does all of the above.
I'm pretty sure I found the side by side comparison on the Superchips site. I don't know if the "HP gains" are simply advertising, but I suspect it's more about adjusting shift points and shift pressure for the autos. If I had a manual I'd probably stick to a Flashcal or Procal, at least from my little bit of research.