Subwoffer Enclosure For My Girls 12's Rockford P3's

I really could use some help with this...I can build boxes to precision however designing them and understanding all of the values and graphs is definitely not my forte. My girl has 2 Rockford P3 12's (dual 4 ohm)...wired in series parallel resulting in a 4 ohm load to her amp that has a subsonic filter. I was told by a few on CAF that a ported enclosure would sound best...and Seth said based on the values a sealed one would. Either way I need help I have them in a sealed box now I am interested in trying a ported one to gain some dB's and put a smile on the womans face.

thanks