Hi there, Ubuntu 12.10 Quantal Quetzal is out! However the Dash search functionality includes shopping results retrieved from the internet (namely Amazon), which I personally found annoying.
In order to remove that, just run this command:
[bash]
sudo apt-get remove unity-lens-shopping
[/bash]
This will remove online shopping search suggestions. Your mile may vary, but from my point of view, it does speed-up search result.
Try it!