I thought I read somewhere that the new amp and I think driver was able to yield 2 or 3 dB more output throughout the frequency response band. But, the new FVX15 is said to have 2 or 3 dB less output than the FV15Hp, which means that the new sub would have about the same as the sub that Josh Ricci measured a few years ago for a cheaper price. That's if what I remember reading somewhere is correct.
I figured I would share this with another basshead:
http://www.data-bass.com/data?page=s...d=115&mset=127
If that Seaton sub doesn't work out maybe you can build this 24" sealed sub. I think this should have enough clean output for you.