I would take Talon's advice and first call them for guidance. You may have a undiagnosed problem with the speaker or it could be something as simple as room placement. I have had the Khoruses for over a year and if anything, they excel at being driven at high volumes. My system consists of an Essence Stereo Amp, Sony SCD1 SACD player, Tact RCS, and Stealth Speaker cables.
The folks at Talon are a pleasure to deal with and will back you up. My 3 year son stuck his fist into one of the Talon woofers, inverting it, and Mike, while on a visit to NY was kind enough to replace it at no charge, himself. You can't ask for better service than that. My experience has been good enough that I've just purchased the Khorus xs and am awaiting their delivery.
I purchased the Khoruses after owning Maggies (3.6) and Verity Parcifals, and after extensive listening to Revels (Salon and Studio), B&Ws (801), Dynaudios (3.3), Genesis (350se's), Audio Physic (whole line), Aerial (10T), Wilson Watt Puppies (5.1 and 6.0), Sonus Faber (Amatis), all excellent speakers. I highly recommend putting the time into making the Khorus' work for you, it will pay off.