I am not a fan of G.skill memory having had problems with them on an i5 build I did recently having to replace them with some Kingston memory because of compatibility problems. However G.skill memory is cheaper.
I think that 520W PSU should be fine. People often over estimate the size of the required power supply because of problematic cheap Chinese power supplies. As the power supply you are getting is reckoned to be a good one you should be fine.