Sealed doesn't always mean tight, take my bros sub for example
Anywho.... From what I've heard, the STF-1 seems good and can hit does to 25hz says RJ and Jaxvon. The Velodyne DLS-R 3500 would also work, and it is quite loud, and goes pretty low (around 28hz maybe). There are many good musical 8inch subs, listen to all you can.
Sheep