miyu...
I don't find your AR/Thiel setup a mismatch at all. In the past I ran a couple of AR preamps, an LS2, then an LS2b, and an LS 3, and I found each to mate exceptionally with my Thiels.
My listening levels are conservative to say the least. My CS2.2's were played with a 35 watt per channel integrated amp - the beginning of my suffering from a chronic, then undiagnosed, case of severe audiophilia. There is no cure, besides, the disease is fun.
Remaining high on my list of manufacturers that seem to have an affinity for Thiel are Acoustic Research, Balanced Audio Technology, Pass Labs, Threshold. Of these my top choices are Pass and AR.
I'm currently digging my Simaudio 340i integrated with my 3.6's, my quest to "dumb down" from all the wiring and procedural complexities encountered with separates. So far, so good.
Turn it on, turn it up!