After a few days of reading around here I decided to jump right in with a new project.
I wanted to add some additional low end punch to my system. I opted to add a second 15" sub to compliment the Vega and to hide it under the dogs ottoman. I used a 15" Dayton DVC and Yung 500W plate amp and constructed the box of 3/4" MDF with ample bracing. This thing really shakes the house and is exactly what I was looking for.
Worst part of the project was removing what seemed like 1000's of staples holding the fabric to the frame. And to my surprize the box fit exact !