hmm sealed or ported for Pioneer 12" TS-W306C?

well on sounddomain it said ported wasn't recommended....... but im just asking to make sure cause maybe it was a mistake. when i searched the forum, i saw somewhere that it only said for the SPL series not to be in a ported box?

so some subs can only be put into a sealed or a ported box? i want a ported one though since everyone makes it seem like you get more out of your sub in a ported box.

any opinions/help would be a preciated!!!!!! thanks!