The RAM that you need is the cheapest RAM you can find running at 1333 MHz 9 latencies, 1600 MHZ 9 latencies. There is no benefit from spending twice the price on 2133+ MHZ RAM. The performance increase is not there. Not cost effective at all. 1% performance increase for double the price - not worth it.
Just get the cheapest 1600 CL 9 kit from GeiL, Kingston, Corsair, GSkill, Mushkin ADATA and you will be fine. l