Hi. I have the LaFolia and Dunlavy Alethas at my home. Although I have no concrete evidence, I have heard that the focal polyglass woofer was no longer available and so a polykevlar (also by focal I believe) is now being used. I have not heard of any problems with supply of the Dynaudio drivers, but who really knows.
In regard to the Sonata II vs. LaFolia issue, at one point, Mr Yun told me that the Sonata II had more slam than the LaFolia, but the LaFolia was more transparent. After having the LaFolias, I have a hard time envisioning a speaker with more impact or slam in as small and svelte an enclosure.
Compared to the Dunlavy, the LaFolia is more laid back in the midrange (with my gear at least) with the vocalist in plane with the remaining soundstage, while the Dunlavy puts the vocalist and midrange more upfront or forward. The net result is that the Aletha possibly sounds more "you are there" on great recordings (audiophile stuff), but suffers on the more mundane popular stuff that many including me listen to. The LaFolias just sound inherently musical no matter what you throw at them. The Silverlines will also play louder than the Dunlavy without strain and sound better at low volumes than the Aletha (perhaps the acoustic suspension design needs more power to get the acoustic (air) damped woofer going. PS: the "you are there" experience of the LaFolia does take time to evolve and requires over 100-200 hours. Mine are still breaking in each day with new strides in transparency and realism.
Fanfare Millenium tubed preamp (no longer made)
Plinius SA 250 MK IV power amp
Electrocompaniet EMC II 24/192 CDP
VPI Aires Scout w/ Clearaudio Sigma into Plinius Jarrah phono stage
Interconnects: Siltech FTM 4 G3 and FTM 4 Gold, or Nordost Valhalla (playing with 1 piece to see its effect, or Acoustic Zen Silver Ref. Mk II.
Speaker cable: Purist Audio Collossus biwire
Power cables: Custom Power Company Top Gun Special and Top Gun HCFi.