I would stick to 2 x 8gb sticks, 2 Less sticks means less of a chance of having one go bad down the road. As for speed I would go with 1866 with 9,9,9,24 latencies. You get a decent jump from 1600 memory in bandwidth and it is still pretty inexpensive. Go to a higher 2133 memory the cost outweighs the performance gain you will get.
1866 is the happy medium.
As for voltage 1.5v is as high as you need to go,also if you have a air cooler that might interfere with your memory slots then do not purchase memory with tall heatsinks.
Here is a nice crucial 1866 2x 8 gb set that uses 1.5v and has tight 9,9,9,24 timings those are nice tight timings that are usually used with 1600mhz memory. http://www.newegg.com/Product/Product.a ... 6820148740
159$ Crucial Ballistix Tactical
here is some nice 2x8gb ddr31600 with 8,8,8,24 super tight timings
I even checked for motherboard compatibility for you and they were not listed, but they did work in a ASUS P8Z77-V Deluxe board that is pretty much the same board you have with some extra goodies. On top of that they were able to overclock them to 2200mhz If you want to overclock your memory, Also you can adjust your turbo so all 4 cores are at a 38x multiplier and turn up your block to probably 105mhz perhaps higher giving you 4ghz. But that is something you will have to play with.http://www.newegg.com/Product/Product.a ... 6820148561
120$ Crucial Ballistix
Both sets are made by Crucial that is a good name brand. With X.M.P profiles, so they should work fine at there rated timings and voltage.
2600k@4915mhz CM Nepton40XL 16gb Cas9 1600mem 2x EVGA GTX770 4gb Classified cards in SLI@1280mhz Stock boost core and 1995mhz mem SBlaster Z powered by TX-850 PSU 2xHTPC's Both w/i3 2120's,1xasus LP HD6570@850core 1000 ddr3mem 1xHIS hd7750@1125core1400mem