Ummm....the link you posted and the picture are two completely different subs. The one in the link runs about 30 watts rms and sounds like a factory speaker out of a Geo Metro. It is also priced at $169.95. That seems like a bit more than "a little over $100", as you said.
Discrete...in appearance and sound, eh? As for the box in my post, it does fit in the back of the footwell or behind the seat where it is not seen. No matter, anyway. The sub is what I'm interested in. I plan to have a fiberglass enclosure built into the rear deck or under seat this summer.