The PRV Audio 18SW2200 18" Subwoofer has a friendlier qts............ Looks reasonable for the box size combined with extension and xmax.
The .391 would make for a 4th order F3/tuning around 33hz but need a bigger box (around 200L or 7ft3). You can tune lower, I'm tuning to the F9 of 27hz in my ported. Sub in a corner and placement on a slab of concrete, I'm pretty happy with it.
The other driver has a qts of .241, I'd say unusable except for a bass horn, and that'd be too huge unless in a building.