I'm with the try out a new amplifier camp, Perhaps a different speaker cable first as that may suffice until you can save if need be? Just from my experience i can tell you the AMP makes a huge difference in what your listening experience will be. I run the 2.4's with a BAT VK-600 and they sing beautifully together and provide more than enough bass in a 13x11x11 room but its so much more refined a presentation that the massive power supply can give. I'd look into dual mono design or monoblock amps with at least 300w per channel. In fact with a fuller and richer sounding speaker cable its almost too bass heavy. I've read those Kimber's sound good with the Thiel though.
Happy hunting
Happy hunting