These seem a bit pricey $$$

Don't get me started on the prices of high-end phono cartridges!

Hello,
They are a little unusual. They have a side firing sub and only play down to 30Hz at -3db. Also the efficiency is 87.6. They handle up-to 200W including the sub. Last but not least they are in a rectangle or square box. If you charge that much at least change the angle of the box to disrupt the internal sound waves like Sonas Faber line. I would say no more than $6k. The plinth is nice to isolate the bass. I would love to hear them maybe at Axpona in the late summer or fall. PS Audio has a speaker at that price range but will probably blow it out of the water. Also they developed a bookshelf speaker that plays down to 30Hz that will probably cost half of what the 900s cost. Maybe the dampening material is toilet paper. That stuff is very difficult to find now. 

30hz bookshelf? not likely 

Depends on the definition of “bookshelf”. And the sensitivity. The AR 3a was marketed as a bookshelf speaker in the 60s. Ditto the Smaller Advent, which was the paradigm for a true bookshelf sized 30 Hz capable speaker...with low impedence and sensitivity to match.