I'm assuming you mean sealed? If the box is too small, it will be too springy so you'll need more power to get equal sound volume... Bigger boxes are just less restrictive so the bass won't be as punchy but it will be able to get louder and therefore won't need as much power as a smaller box to get the same volume.
There isn't really a disadvantage of big boxes except of course for the ammount of space they take up.
1995 Camry LE 4 Cylinder Automatic Sedan
Green Silver Pearl Metallic Clearcoat and/or Silverleaf Metallic
No performance mods
Clear bumper lights
Boston Acoustics ProSeries 6.53 in doors and Q-Logic kicks
Polk/Momo 4 channel amp