one thing I would change is your PSU. its a tier 3 PSU and you want at least a tier 2 (if willing to replace every 3 years) or a tier 1 (replace every 5 years).
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
also the 850 EVO in an m.2 form factor will give you no benefit over one in a SATA 6G. You need a 950/960 pro/evo if you want to use the bandwidth m.2 has to offer. Plus if dead set on the 850 evo a SATA will not throttle under load as much as an m.2 drive will. hope that helps.