Mazersteven is correct. You could, for example(an extreme one, albeit), put a JL W7 8" driver in a proper ported cabinet with sufficient amplification, and it would likely exceed the performance of most so-called 'high end' 12" sub woofers.
As for that AudiSource being superior to the Dayton? Not likely. The Daytons are widely known to be the best possible value units available for their price bracket. But this is a typical thing for Dayton(Parts Express). They make many drivers, for example, that cost a fraction of what a name brand high end costs, but perform identically in the relevant areas of performance. Dayton has no middle man. They engineer and have the drivers built in mass directly from the Asian (and in some cases, American) factories. There is minimal mark up, and as such, you get more for your money. I have been repeatedly impressed by Dayton's raw drivers. As an example, the RS150 6" mid-bass driver from Dayton costs around $30, yet it performs on par in all measurable ways with Seas Excel driver equivalent that costs 5x as much! Now that's value. Don't get me wrong: I'm not saying the Dayton 8" powered sub is on par with name brand units that cost 5x as much. I was only giving a specific extreme example for emphasis.
-Chris
