I am running Thiel 3.6s on the short wall of a 13' by 21' room, and I am driving them with a pair of Rowland 201 monoblocks. I listen to classical music exclusively, and so far I'm very pleased. The 201s are 250W into 8 ohms and 500W into 4 ohms; I would be hesitant to drive the 3.6s with less power than this. I was using an Aragon 8008BB (200W/400W) before the Rowlands, and although it was able to drive the Thiels, the Rowlands sound more refined, especially on peaks.
Good luck!
Good luck!