The shop insists a 3-way is a 3-way.Speaking frankly, this comment by the shop is nonsense. Some 3-ways (and other kinds of speakers) are best suited to be driven by solid state amplification, some are best suited to be driven by tube amplification, and some are equally at home with either. A speaker having a nominal impedance of 8 ohms or more, and having impedance that does not vary greatly as a function of frequency, and having higher than average sensitivity, will usually be suitable for use with either. To the extent that those criteria are not met, things become questionable.
Over the years many of the models Wilson has produced have been used successfully with both kinds of amplification, even though many of those models have had 4 ohm nominal impedances (like the Sabrina). However, the graph of impedance vs. frequency for the Sabrina that I linked to in my first post in this thread, coupled with the associated comments that I quoted, as well as a comment in the main body of the review, as well as the Sabrina's somewhat low sensitivity, raised caution flags in my mind as to the suitability of that model for use with tube amplification.
However this comment:
... The Wilson people I spoke to at Wilson Audio love VTL, VAC, ARC, and Nagra tubes with the Sabrinas.... as well as the comment you indicated earlier that Kevin Hayes had provided, as well as the video Knghifi linked to showing the Sabrina being driven by a VTL tube amp, as well as the inclusion of a 1 to 2 ohm output tap on the VAC iQ models, do provide a fair amount of confidence, albeit obviously not as much as an audition with your speakers would provide.
Best of luck as you proceed. Regards,
-- Al