Hi
A few bits to this:
If you are running full 3 tier with the SQL server and the NAV application on different boxes (Full 3 tier) you could run into some trouble, but i assume SQL and NAV are on the same box
You say the server name wont change which is a good thing as SQL can retain the old name in some places causing so weird behavior
If the IP changes no problem at all, NAV and SQL will have no problem at all
So bottom line, location move with IP change, not problem at all i have done it before myself without issues
Cheers
Nev