I have a pair of 2.4s. They dip into the 2 ohm range so it is important be stable down low. I don’t think they are too power hungry but they have a rising treble on axis. I found EQing down 2db from 8k up really helped the speaker.
the best sound I got out of my thiels when I used them in my main system was on a McIntosh 462 off the 2ohm tap. The 2 ohm tap softens the highs and really balanced the speaker. The 4 and 8 ohm tap were too bright imo.