Why wouldn't you? I thought it was good that they showed a low-end of 23Hz, but listed the -3dB point at 28Hz. Maybe I'm just a sucker for extra false info.
To the OP, you'll also get some room gain to help out with the lower frequencies. At ~$400 or below, there are a number of options out there. Have you looked into any of the internet direct brands, such as SVS or Hsu? The
SVS PB-1000 is $500 (total, including shipping) and is rated to 19Hz at -3dB (and they show the response graph).