Got this email today from
sonicelectronix.com with a 25% off coupon code (NVX25). It's a NVX 8" self powered low profile sub, the
NVX Audio QBUS8 going for $199 which makes it $150 with the coupon.
A couple things I like about this one is the fact that the amp has a built in cross over, a subsonic filter and even a remote level. At 80 watts it's 20 watts less that the RetroSound version that the OP posted, but I think the price with the discount and the options the NVX has makes it a little better buy. I also like the rubber isolation mounts (at least they look like rubber).
Here's some pics (sorry, the pics are big on the site):
