sub boxes

is it a bad thing to have an undersized sub box?
I built a box for a 12" bazooka sub and just upgraded to a 12" memphis... The way i have it all set up its a real pain to make another box that is bigger... I only needed .87 cu. ft. before but now i need a full cubic foot. So is it really that bad to just use an undersized sub box?

really i just need to know if a box that is too small will affect quality or volume, or more importantly will it cause any damage to the sub. (Its a sealed box, not ported or vented)