I am not a huge fan of RC; so this may kill me...
http://www.reefcentral.com/calc/drain.php
Is a calculator that you can use to figure out roughly what the pipe diameter of your overflow will handle (and from the other figures that I have, they are fairly conservative in the estimation.) In your case it says that your overflow will handle 2200 GPH. You need to plumb for what the pump will return rather than the size of the pipe used to return the water... So yes, your overflow will easily handle it.
Now, as to weather it is overkill... what are you planning on keeping? If clams, then yes- it may be too much flow in your tank as they come from calm areas. If it is SPS, then you are good to go (heck, add another power head if you want. Have you ever seen the volume of water that flows over a reef?)
Good luck.