I've been looking at the difference between 2666 and 3200 and it's usually 0 - 4fps depending on the game, so I definitely don't think it's worth it.
You're probably better getting 3000-3200 with tighter timings. I went the opposite, as the only place I could get GSkill Trident Z RGB 2x8GB at under £220 only had 3600mhz CL17Interesting stats, really not worth it then.