... unless you have a some downtime during the change. make sure to lower you TTL on the DNS entires to push the change through. Good luck...
And, even if you had some downtime (assuming is was less than a couple of days), any impact to SERPs should go away quickly. One can limit downtime by overlapping the old site and the new site for a few days. Brian
Where you would run into trouble, is if you changed any of your URL's. If so, you will want to do a 301 permanent redirect.
change of ip address should have no change! i noticed a little disruption for a day or so but things settled down to normal when i did it a month or so ago