Hello,
Link should answer most of your questions....
As for sump vs no sump...have your tank drill with two or four holes (two in each corner) regardless of which one you decide. If you are not comfortable with a sump...then at least your tank can be quickly and safely modified to handle a sump. The extra two holes will ensure flexibility in your overflow design.
Successful reefs can be kept with or without a sump.
http://saltaquarium.about.com/librar...y/aa061900.htm
- Victor.