Large threads like this are good for maintaining a specific community. On the other hand, large threads like this can become cumbersome to sort through for very specific considerations.
With that said, let me again point out, as I oft have; that over generalized recommendations about amp compatibility with Thiel’s can be misleading.
In past times, Thiel recommended amp brands for the speakers made at the time. Later models have different powering needs. Those previous recommendations may no longer apply to later model Thiel’s.
I’d also suggest caution in reading too much into what Thiel or any other manufacturer used at shows. One might assume that accompanying gear was specifically hand selected by the manufacturer to demonstrate the utmost capabilities of their own gear. The truth often is; that rather than transporting crates of heavy equipment over great distances, the manufacturers depend on local dealers to assist in providing gear for demonstrations. Those local dealers might have their own convenience or agenda at the top of their priority list.
Not to pick on any specific brands, but the some of the often recommended amps from companies such as Ayre, Bryston, Pass, PS Audio, etc. might work wonderfully with some Thiel’s, but are not designed or spec’d by those very manufactures, (independent testing, such as those found in Stereophile will also confirm this) for the sub 4 Ohm loads of some later model Thiel’s.
Be wary of dealers selling(!) you otherwise.