Changing URL of WPMU Buddypress site.. Need advice please.

I am running Buddypress Magazine theme here:

This is where I have been building the site but the plan is to put it on the domain
I have pointed the name servers for to my server and added it as an addon domain.

Please can someone advise me on the best method to get the site working on
I want it to be running on the root of rather than for example.

I know how to search and replace in Mysql but don't want to go into anything too soon without getting your suggestions first.

There is one blog attached to the site and it is domain: path: /carsite/