I own the big brother of the F120A drivers, the mighty F200A (8 inch diameter, rated 30 - 20,000 Hz, 90 dB/w/m) in mass loaded transmission line cabinets. I drive mine with a 6 wpc Clari-T, but extra headroom would be nice.
Compared to other Fostex drivers these are much more musical/full bodied with less dynamic or forward of presentation. Nothing else close to $375 each will get you into the 30 Hz neighborhood from a single driver.
The F120A would be great for a small cabinet/room or if you wanted to add a sub.