A:Answer From what the manual states the max supported SSD is 512GB, ive read a lot of reviews and id say your best bet is the 960 Pro, its about $280 vs. the 960 Evo $240 Id stay far away from the intel 600P, the benchmarks show the pro and evo to be about twice as fast as the intel.
http://ssd.userbenchmark.com/Compare/Samsung-960-Evo-NVMe-PCIe-M2-250GB-vs-Intel-600p-Series-NVMe-PCIe-M2-256GB/m200373vsm169054