Regarding headphones and amps, I believe they will pair well (if Sundara is not like classic HFMs). I am also waiting for my elex.. Potential concern might be rather sources. This amp is quite resolving and scales very well with quality source gears. My beloved RME ADI-2 is arguably a very solid (ds) dac choice under $1k. But lyr 3 continuously pushes me to upgrade to higher-level dacs. Audition experience of great dacs taught me what additional details exist in the red book, and Lyr 3 convinced me capable of reveling THAT LEVEL if dacs are good enough.