BleuBox requires a hole be cut in the wall. If you are unsure if you have the proper amount of space and clearance between studs, we recommend that you consult a professional before installing. Installation instructions can be found here.
Yes you can. As long as you have enough clearance inside your vanity and the vanity is constructed out of material that would allow for a hole to be cut without compromising it's integrity, you can install BleuBox the same way you would inside a wall. We highly recommend that you consult a professional to make sure the material your vanity is made of is able to support the weight of BleuBox.