I just had the chance to directly compare the HRS130 set up with my McIntoshes with a 25W tube amp from Unison Research (very decent, but not explicitly high end). While the HRS130 are very fast, they are not particularly efficient (87db/W/m) and usually are being not considered optimal for a smaller tube amp as compared to e.g. horn speakers. However, I have to say that the Unison has really made a good impression on me and my audio buddy in direct comparison with my McIntoshes. Also, power was not an issue in the 50 sqm room.
The tube generated more room (than the impressive stage the speakers had provided already), a deeper and wider sound stage and a fine resolution particularly in the mid range. Is it possible that this easy-to-spot difference is due to the fact that the GP speakers do not have a cross over filters splitting the midrange, and a warm tube amp with a pronounced midrange can take advantage of that? Mere speculation!
Anyway, three hours of intense listening and I have just ordered a DECWARE Torii Mk5 expecting that this should be an even more pronounced improvement. Unfortunately, it will be under the Xmas tree in 2023, if I am lucky.

