Thanks Tom.
My issue is that I simply couldn't use any of the Thiel subwoofers (despite that I sometimes see them for sale on audiogon!).
My 2 channel listening shares space with my home theater set up, so the room is packed with speakers already, and the only place I have for subs is under my projection screen along the front wall - behind my Thiel 2.7 speakers. The Thiel subs are all too large and would intrude in to the picture area, so I had to find the smallest subs I could buy, of good quality. Fortunately the JL Audio E110 subs fit just right, and come with truly excellent reviews.
But...it is such a headache to do the whole sub thing right that I just haven't got around to it. Some people spend frightening amounts of their time integrating subs. It's not uncommon for me to read "after several years I've finally got my subs perfectly integrated!" Yeesh!