RAM - Timing vs. Speed

I'm assuming speed is the thing to go for, and timing is the thing you look at after the speed >.>

Just to confirm in case I do something stupid-
Native 2133 MHz @ 11-11-11-30
is better than
Native 1866 MHz @ 8-9-8-24

But what if I over clock the 1866 to 2133?

Well I overclocked my 1600 7-7-7-24 1.65v to 2000 9-10-9-27 1.65v,tested it, was stable, then benched, I barely noticed a difference(slightly higher mem bandwidth), go for cheapest speed so that you can oc your cpu easily.