prefab boxes are 'ok' but if you want the best sound go to a local stereo shop and have them ake you a box specific to your subs. there they can tune it to you specs like sealed,ported. made for rock musuc,rap, power the amp puts out also matters.

and its sometimes cheaper to have one made. dont go to circuit shity,best buy or some big name lke that. its the smaller shops that really know how to make boxes.

the shop i got to here has a software that helps design the box to your needs