These are car audio 'IB' sub drivers so OB, very large sealed, or aperiodic is best, with the latter yielding the highest SQ. It's specs are ideal for a 'classic' stuffed TQWT and going isobaric will keep the line's CSA reasonable, so 12" square (inside dims) should work fine and a ~93.63" pathlength will tune it to ~30 Hz if stuffed along its length with ~48 oz of R-19 fiberglass. The beauty of this design is that the specs can be off quite a bit and still perform well by adjusting the amount of stuffing.

Catalog specs:

Fs = 30 Hz
Vas = 6.83 ft^3
Qts = 1.04
Pe (RMS/max) = 75/150 W
sens = 88dB/W/m (+/- 2 dB)
nominal 8 ohms

GM