svs pb-13 ultra

hi all i just got a svs pb-13 ultra. i have a couple questions tho. my room is 12x14 with an 8 foot ceiling. it is quite small. one question is the manual states that you can tune the ports with plugs, but it doesnt describe the effect of sealing up all the ports. does the bass get much tighter? do you lose bottom end? would this sealed application be better for my small room. i also have it fully treated with bass traps and have am external eq to flatten the subs response.

second question, if i tuned the sub to 10hz by plugging 2 ports, will this be a waste of time because my room is not long enough to produce a bass wave that low?

thanks all