Sorry, can't help you with the Thiel 2's. FWIW, the Theil 1's and 3's were fairly easy amplifier loads. I'd suggest contacting the nice people at Thiel:
http://www.audiogon.com/cgi-bin/manu.pl?thiel&1&showmanu&Thiel+Audio
The earlier Thiel CS series weren't that difficult on amplifiers either. They stayed above 4 Ohms. Even the bass EQ'd 3.5's offset the demands of the EQ by gradualy pushing the impedance up where the bass EQ's kicked in.
http://www.audiogon.com/cgi-bin/manu.pl?thiel&1&showmanu&Thiel+Audio
The earlier Thiel CS series weren't that difficult on amplifiers either. They stayed above 4 Ohms. Even the bass EQ'd 3.5's offset the demands of the EQ by gradualy pushing the impedance up where the bass EQ's kicked in.