Changing background color

I have been developing with the community version for a few years. I am at the point where i need some help with some mods and am not feeling great about using an older version from the support POV. I have no issue paying for and moving to the enterprise version. I just want find out if i can do a few things.

I need users to able to switch into a mode that uses statistics. I want to change the background of the crud when the user toggles this mode. Otherwise the crud will look the same. Can i do this with enterprise?

How difficult will it be to upgrade from community to enterprise?