hello, my name is Kristijan, and i am from croatia.sorry, but my english sucks

i have few questions:
i have pioneer 3004spl subwoofer, and very healty 1000 wrms amplifier ::)
i wonna buy db2 for 12",and on the plans looks like that's box for 2 -4 subwoofers?i have only one...
and another question...my subwoofer has 7-3/8 mounting deepth..and i think it will be better to set magnet to vented side...will i have a problem? thnx!