I've read most of the comments on the MCM High Excursion (55-2421) 8" woofer, and it seemed like most people liked. I've put the specifications into Unibox and they didn't look very impressive. So, I decided the jack around with adding four woofers in parallel. Still...not too impressive. The sensitivity boost was great, but that was it. Then I started playing with changing the series resistances (RS) in Unibox. 4 drive units in parallel with RS(series resistance) of .9 ohms yielded a 20.3Hz @ 107.3db's with 480 watts in a 128L vented box. Wow! I decided to increase the RS to 1.2 Ohms and increase the box volume to the tempest adire alignment of 213L. The four woofers put out just about the same amount of DB's as the tempest with LESS power. Am I missing something here? It seems like a viable option when you can buy four woofers for $27.49 each in quantities of four with free shipping until June 15.