Question about Crucial Mx300

I looked, and it's true that there is still a second M.2 slot under the existing one (http://hexus.net/media...).

This is an MKey M.2 and therefore the Crucial MX 300 would work.

The Gigabyte Aero 15 probably doesn't have a second M.2 slot, but you could swap the previous one with this one.

Bear in mind that you will have to reinstall Windows, as the previous M.2 has the operating system on it.