Is it possible to switch Spotlight in OS X to using Google?
In OS X 10.10 someone has made a spotlight plugin which has unofficially reversed engineered the API necessary to add new search engines.
i.e. google. The project is called flashlight.
It comes out of the box with a lot of plugins, including google.
To use it, you start spotlight and enter g yosemite, for example, which does a google search for "yosemite"

This open-source app is hosted on git hub and has releases which mean you just install the .app file, as usual. However, it's not signed so you may need to go to system preferences -> security &amp; privacy and choose to allow the app to open (which you do after starting it and getting the error message that the app is not from the app store). Assuming you trust the app and/or my recommendation. You may like to visit the github site and see how many people have starred this application, to give you some sense of confidence.
download here:
http://flashlight.nateparrott.com/

github:
https://github.com/nate-parrott/Flashlight#flashlight