A bandpass enclosure will give you a very boomy response from your subs. The frequency range of a bandpass box is pretty narrow. It'll only be loud in a short range or frequncies. A sealed or ported enclosure will give you much tighter bass and your subs will sound much better. Bandpass boxes are also more expensive and much bigger than sealed or ported enclosures. I would stay with a sealed or ported, they will be just as loud if not louder and perform much better than a bandpass.
Steve