1. if you are looking for the best graphics card, look at tom's best graphics card for your dollar and find something that will fit your resolution's needs as well as your upgrade time line. See what Nvidia/AMD offer and then check out benchmarks of games you play (plan to play) to see which performs better. Finally make sure your you have a quality PSU to power said card.
2. the GTX780 is a great performing card and the XFX psu you selected will have no issue powering that card.
3. yes your PC specs are good
4. any card you receive from the brand is technically "factory clocked" as long as you yourself don't OC it. Some cards come factory OC from AMD/Nvidia spec settings but are still factory clocked. Most of these factory over clocked will state so on the packaging with marketing lines like "over clocked" "super clocked" "OC edition", etc., You can find AMD/Nvidia spec settings on their specific web sites.
will that result show what I max max my overclocking on the gtx 780? If I get that card and I download msi afterburner how do I know if I need a higher psu? When do I know when the card will "die?"