^^^How low do you want to go? If you are chasing single digit bass then sealed (in multiples) is the only reasonable way to get there. If you are shooting for a low end around 15 Hz, then either a pair of XV15's or XV30's would be my preferred option. Different tools for different jobs. In 3,000 cu ft space its tough to predict if you will get sufficient Pressure Volume Gain to offset the earlier rolloff of sealed subs vice the ported.
I agree with basshead81, asking Tom for advice is the best option. He recommended ported for my 5,000 cu ft basement.
Current Gear: PJ – BenQ PE7700; Receiver - Onkyo TX-SR805; Blu Ray - OppoBDP 103; Turntable - Dual CS-515 w/ Ortofon Super OM10; Amplifiers - OdysseyKhartago, Adcom GFA555, QSC RMX 1850HD; PEQ - Behringer FBD2496 [Near FieldSub], miniDSP 2×4 [Flanking Subs], REW; Speakers - 4 Pi (w/B&C DE250/JBL2226H) × 3 [LCR], Yamaha Crap × 2 [surrounds], Exodus Audio Maelstrom-X18" sealed sub [near field sub], LAB-12 based ported sub tuned to 22 Hz x2 [flanking subs, XO set at 40 Hz]