in order for a ported box to sound it's best, a lot of engineering will have to go into designing the enclosure. Matching a sub that will go best with the size shape and port of the enclosure as well as the ports can be tricking. Sure you can get a ported box and put any sub in there and it'll shake the rear view mirror. Ported box will requiring a larger box. Say a sub in a req. sealed box that needs to be 1.25 cu ft/chamber will need 2-2.5 cut ft/chamber in a ported box. Ported box gets louder most SPL competitor uses ported boxes, but for an everyday listener a sealed box will be better off with a sealed box since it requireless space most important of all it can achieve a mixture of sq/spl that way you can have the best of both words. a properly installed sub in the correct sealed box can get just as loud as a ported box give a take a couple of db's
because our legends are very tightly build, bazooka subs won't really get very loud, they do sound very tight with very little power if you're not looking to get loud 2 10's will usually be loud enough for a first system. But I rather go with 2 10's in a sealed box or 2 12's. How much are you looking to spend? What do you have already and what do you plan on purchasing?