Thiels are notorious for being hard to drive.

I've had 3.5 in the past which my Rotel 100w would NOT drive. It would shut down.

I no longer have those speakers but really love the 2.3 and don't want to encounter the same problem.

The 2.3 are rated at 4ohms but for must of the range they are around 3ohms according to a review in Stereophile.