I'll try to find out something from Rob about the 2.7 vs 3.7 failures. Same driver.
Thieliste, good investigation. In the day Thiel, especially the CS5, was very successful in Japan. Luxman amps were the clear choice in ultra high-end systems. They are seriously good. The amp you reference is still doubling into 1 ohm, and their engineering choices are musical (most Japanese amps are not, in my opinion.)