I own the Ultimate One Soundlabs and have them in a room larger that yours. Last week the two visitors listening with me remarked how wonderful my overall dynamics and bass extension was.
While I am not likely to persuade them to change to U-1 Soundlabs over the experience, they were impressed. One of these guys owns Dynaudio Evidence Temptations powered by ARC Ref 600 Mk 3 mono blocks and a Walker Turntable. The other has big Wilsons powered by BAT and an SME turntable.
Point being, big Soundlabs are in the running as an ultimate speaker and based on their retail price, one of the more economically priced high end products.
As for amps, I agree with the comment about running tubes. Mine are powered by Wolcott 220 watt mono blocks (EL-34 based) and will produce peaks of 99 to 101 DB at 13 feet with both CD and LP.
You can click on system beside my name if you wish to view the A-1 and Ultimate Ones. I have images of my old and new system both posted at that link.
Dont be afraid to contact me. I am willing to offer you help if you are in need.