Listening through my Audioengine 5 speakers, there do seem to be clear differences between the two tail pieces (and thank you for giving such a detailed demonstration with such varied musical passages). Overall - after one listen - the difference I seem to hear is that the Frirsz tailpiece sounds more open and smoother in more passages than the Thomastik. At times the Thomastik sounds (or seems to sound) a bit more nasal and more 'punchy' than the Frirsz, and not quite as open and smooth. Not technical descriptive terms, I know, but just the best I can use to describe my impressions. There were times that I thought I might prefer the sound of each over the other, though more often, I would say the Frirsz would be my choice. Now I wonder if these differences would hold up over time, and with different strings. Would one begin to adjust one's playing to the differences in response of each tailpiece? Certainly not an adventure I plan to undertake, but thank you for making the effort and taking the time you did to demonstrate these two tailpieces.