Yep the 2666, the timings are a little loose as the Fury line includes PnP (self set up) and tighter timings can be difficult, might try XMP or manual setting through the BIOS, might even be able to run CL14
I'd get the 2666 and then try to improve the timings -- the stock 15-17-17 timings are crap. You should be able to run 15-15-15 or even lower at 2666 speed.
Yep the 2666, the timings are a little loose as the Fury line includes PnP (self set up) and tighter timings can be difficult, might try XMP or manual setting through the BIOS, might even be able to run CL14