Are you aware that you want to use a driver, that is optimised for upper bass, for lower bass? You're going to need some special enclosure to get this to work, as with any normal enclosure, you will walk into the problem of the short Xmax of this driver.
Also 40 - 60 Hz is an extreme short bandwidth. It would most likely mean that every note from this enclosure would sound exactly the same, creating a very one-note-sound. If that's not a problem then I would opt for a narrow tuned 6th order bandpass (40 Hz and 60 Hz tuning), which would give you a highly efficient one-note bass.
Perhaps if you would describe the rest of the system, there's better solutions to be found (there's gotta be ).