Okay I have been using Nui for a while now and have everything all set up the way I like it. I am planning on upgrading to nui+ and am aware that I will need to manually update nui+ and stop using the curse updater to update nui. For the initial install of nui+ do I need to delete nui, and in the process lose my settings and my wonderful beautiful setup or can I just manually drop the nui+ into the addons folder and allow it to overwrite what it needs to and add what it needs to without losing my settings?
Your best bet to minimize the potential for issues is to delete the nUI folder within the Addons folder. You should not lose any of your settings as they are saved in the WoW\WTF folder which is completely separate.
You can overwrite the nUI folder if you really want, but you may encounter errors.