Indeed, I gotta agree with Lovin here... as much as I would love to encourage your spending more on SVS now... especially bigger SVS... like the 3000 or 4000...
If you can score that deal on those yamaha subs, you'll get the taste of what could be.
The DIY path has a lot of merit. I'm reading the books myself so I can learn how to. In no time, you can build up your own forest of 18" subwoofers! But at least then you'll have subs to play with while you build some SUBS!