Just for the record, I have auditioned the Thiel CS1.6's at a local dealer, and they sounded absolutely wonderful in his set-up being driven by a VTL ST-85, a compact stereo tube amp employing a pair of push-pull EL-34's per channel coupled to the speaker through an output transformer optimized for power delivery into 5 ohms. Although this model continues the Thiel tradition of 4 ohms nominal rating, with a flat curve and the >3 ohm minima falling above the bass range combined with mild phase characteristics, it also breaks some new ground for the brand by offering a rated 92dB sensitivity, which Stereophile actually measured to be a true 94dB (older Thiels averaged around 86-87dB). Given the 6 1/2" woofer size, this implies that any good quality, moderately powerful tube amp that is rated into 4 ohm loads should be able to drive this speaker just fine in medium-sized rooms, as I experienced.
P.S. - Tweek, you have often expressed a penchant for listening with your eyes, so I'll just comment that if a speaker's 'driver count & cabinet size to price ratio' was any indicator of its quality or sound, we probably would all still be listening to the ones we owned in back in our school daze. I suggest making a field trip to hear the 1.6 if you are able, and then tell me if you still don't think it offers great value for the money.