Sub box ported/sealed

[sub7]

I am currently running a sony 12"P5 350rms sub in a prebuilt sealed box .
I am now for buyin another sony 12" sub and was wonderin if i should buy a dual 12" box sealed or ported. I have been informed that there is a nicer sound off a ported box, is this true ? Is my sub able to be used in a ported box ?

[Jack]

I have those subs, in separate boxes. They sound better in a sealed enclosure, in fact I think it says in the blurb that comes with the sub they're designed for a sealed enclosure.

As an aside.... Aren't they 300W RMS? The 15" ones are 350W afaik