I have a NIB SX hybrid sub. Vitas built it for me some time ago. I never used it and it has been sitting in my closet for awhile now.
It has the SX motor, beefier coil/thicker leadwire, and upgrade/more spiders. This is all compared to a normal SX sub. Ratted at 1000 wts rms and if your are carefull, 1200 wts rms. It is a D2.
I wanted the sub for a sealed box but it will work in a ported box as well. I'm not sure how small of a box you are looking to put in but it was recommended for a 1.3 sealed and 1.8 ported, tuned in the low 30's.
$180 shipped with the correct insurance amount, packed well and tracking number.