How can it be possible that 1-13" sub could out drive and out perform 2-15" subs?? That is what boggles me.
I don't know if it would outperform it, but there is no denying the awesomeness of the PB13 ultra. Its not only about the size of the woofer. The woofers excursion as well as the size and design of the enclosure make a huge difference.
I poked around a bit more in terms of quality issues with their subs. No real major issues since the A5-350's were catching fire a few years back, but I've read too many posts from people saying they would never do business again with ED. Even recently. I don't mean to bash ED. There are many satisfied customers I'm sure. I just don't trust them enough to hand over my own money.
Buying internet direct, you can't simply show up at your local AV store if there is a problem. Its a real hassle if anything breaks or malfunctions.