The animate of search is slow (I was using Unity Tweak Tools and CCSM to turn some animation off, but search animate on dash is slow still), anyone knows how to turn it off?
This would not be possible, at least since 12.04 and beyond this has not been possible. Disabling every single Unity animation would require someone to recompile Unity completely, as the animations are hard coded into it. Another option was available at one point and that was "Ubuntu 2D", but that has been marked discontinued for a good period of time.
So at this time being, there is no way of disabling the animations that appear in the Unity Dash. The only option that you could do is make the responses quicker, but that would not relate to anything dealing with the animation.