Thiel Model 2

Have any of you ever owned, or heard, the Thiel Model 2 speaker (not the CS2)? If so, how did you think they sounded, and how demanding were they of the amplifier used with them?

This was one of the earliest models Thiel produced, back around 1976, prior to his designing phase aligned speakers. It was a ported bookshelf speaker, roughly 19"H x 11"W x 9.5"D, with a 6.5" driver and a 1" cloth dome tweeter.

Later Thiels appear to have a reputation for being excellent speakers but being difficult to drive, because they have unusual impedance curves and make heavy demands on amplifiers. Does anybody know whether this was also true of the early Model 2s?