Changing DNS suffix – Windows 2K Server

When I started configuring my first Windows 2K server I was informed that it was staying local so following a recommendation from Microsoft setup of DNS/Active Directory I named it vwplant.local. I have now been informed that in the future we will be adding another server to access this domain via T-1. So is it necessary to give it a legit domain suffix or since it will be coming over our T-1 can it be left alone? If I use dcpromo can I uninstall Active Directory change the domain suffix andreinstall Active Directory?