The x-plosive and MFW-15 make an interesting comparison of differing solutions. BOTH will sound very good for music. If you compare a pair of x-plosives vs. a single MFW-15, in the 20Hz range they will be close, with the pair of x-plosives likely edging out the single MFW-15, but the ports are working harder as the MFW-15's massive port is larger than that of TWO x-plosives. In the upper 1/2 of the operating range, the 2:1 comparison is rather close, with the MFW-15 having some advantage in providing a stronger attack, punch or kick. The x-plosives will hardly lack here, but the MFW-15 is a powerhouse in this regard.
It will come down to available space and preference of both look and sound. We demonstrated at the LA G2G that a single MFW-15 fills the space described above very nicely. A pair of x-plosives will also do very well, and are visually much less obtrusive with their much smaller front profile of 15.75" wide x 16.75" tall. They are about 2" deeper than the MFW-15, but hide next to furniture very nicely. I'll see if I can take a picture of two of the prototypes next to eachother for a size reference.
Of course the thing to remember about having "enough" subwoofer capability is that it is usually only a matter of time before you explore the limits of ANY subwoofer you own. Obviously a pair of MFW-15s puts you at a very significant level of capability, and I do believe will satisfy many for a very long time.
Description: the x-plosive subwoofer is part of the x-statik line. This is one cool customer with IN ROOM down at 20Hz for sure. This will for sure be a Class Defining Product... Beautifully finished and detailed like ALL of the x-series...