Wow! They refer to a 1.9 ft3 sealed enclosure as "small"?

I have my RE Audio SE12 sub in half that size and it performs wonderfully.

 

I'm not familiar with the sub drivers, but AVI components are among the best I've ever heard, and that includes some uber-expensive (and some of those very unimpressive) sets. I loved the AVI's my old boss had (off Adcom amps no less).

 

yeah...my thoughts too, Xmax looks really low..but i guess efficient?

here they are:

 

I have a pair of the AVI SLS 250s (10"s)
The SLS version is more suited for smaller sealed enclosures so I cant really comment on the SL line but I really like the ones I have. Here is a link to their home page if you already haven't seen it, there is lots of info there.
http://www.avisound.com/subwoofers.htm