G-Sync would work with anything. G-sync only requires a Nvidia GPU I want to say GTX660 or higher I could be wrong their. But yea with a GTX780 you will be fine. G-Sync as I'm sure you know by now only really keeps your monitor adjusted to your GPU instead of the other way around which adds a element of smoothness which is great
What I would do differently.
Thermal Paste: Take it off. The Thermal is good with the h100i. And if anything I would get something like IC Diamond which performs stronger or another highly rated thermal. Toms has a article somewhere on how they stack.
RAM: Lower down to 8 GB 1600
GPU: Nothing maybe down to GTX780 non Ti if on a single display
FANS: I personally didn't care for the Corsair fans. I had the quiet edition and the performance may be different. I went with the Noctua NF-F12's probably the best fans you can get for your CPU cooler honestly but also cost a little more to.