They do look far nicer than Tang Bands in their construction, and especially their specs. If the FR curve hasn't been massaged, it's a remarkable driver, should sound very good, as you say; and it will go far lower than the Tang Bands. Also, in general terms, ninety clams is far from expensive; I could use two and series 'em, run off the sixteen ohm tap; that would get me near 90dB.I don't have fifteen watts to burn, though; more like six. Many small, no feedback amps don't like to be run near the limit either, and mine's no exception. The sound starts to 'wall up'.
Aloha,
Poinz