Also agree with the SSD thing. If the drives are just for storage that's fine, but don't expect any performance scaling in loading/booting/spawning/zoning from RAID on mechanical drives. RAID does not improve seek time, which is 90% of the bottleneck when loading/booting etc.
I would probably opt for a different PSU as there are alternatives for under $100 built with better quality components that are more flexible in use. The "NEX" selected is manufacture by FSP using what I would call middle tier components. The split-rail design is unlikely to cause issues, but you never know. A 20A per "rail" limit is only 240W. A factory overclocked non-reference GTX970 runs right at about 240W peak load. More if you overclock it further. It's...