Migrate site from subdomain to main domain

I have been redeveloping a site of mine using a subdomain.

For instance, if my main site is abc.com, then I set up dev.abc.com and have being using that to design my new site.

Now I am ready to migrate the redesigned site from the subdomain to the main domain.

What is the best way to do this?

Will the Snapshot plugin help me with this?

Note – the website has been COMPLETELY redesigned. New theme, new everything.