Atrocious writing skills aside, did you really just compare a GTX 770 to a GTX 650 Ti? Holy shit. I feel like I'm wasting my time, but as I currently have time to waste, I'll take this point by point.
http://gpuboss.com/gpus/GeForce-GTX-...X-650-Ti-Boost
Read that link, lolno. The 650 and 770 don't even compare (how could you possibly think they do?!).
Both cards have the exact same ports...
This doesn't make any sense, and sounds a lot like someone trying to sound intelligent about a topic they know nothing about.
Besides the fact that Windows 8 is terrible, his build specifically lists Windows 7.
Now, to Cyber, I'm going to assume you simply don't want to build your own (as that's what you said), and that you know full well that building your own will save you ~$200 USD, which you are giving up for the convenience of someone else doing it. My suggestions would be to drop the RAM down to 16GB (2x8GB, so that it is easy to upgrade in the future should it be needed), and strongly consider finding a way to fit a 256GB SSD in your build/budget. Upgrading to an SSD was one of the biggest quality-of-life improvements I've made to my PC since I originally built it. It really does make a huge difference. All that top-end hardware doesn't mean anything if your HDD is bottlenecking.
Oh, and most importantly, get a high-quality name brand power supply. You can easily drop to a 600W or 700W PSU with a single-GPU setup. Don't cheap out on the power supply. It is the most important component in a system. If it goes bad, your entire computer can be destroyed in an instant.