Amp matching with high sensitivity speakers

I can’t speak for those who play speakers at extremely loud levels.  If I had speakers as efficient as yours, I would not rule out amps rated as low as 5 watts per channel.  This brings into play low-powered tube amps (my favorite kind of amp), or some low-powered solid state amps, like those offered by First Watt (Pass Labs offshoot).

The thing with tube amps is that it is very hard to find a good one for really low prices because the cost of decent output transformers alone can be quite high. Used amps can keep the price down and are a good option with tube gear because even very old amps tend to be serviceable (many solid state amps are harder to repair because they tend to be more complicated and have parts that become unobtainable).

With speakers of this high efficiency, I would be looking at tube amps running EL 84’s, 6L6, KT 66 (pentode/tetrode pushpull amps), or single-ended triode amps.  Because of their simplicity, some might expect single-ended triode amps to be inexpensive, the demands placed on the output transformer means that decent amps can be quite high in price.  The cheapest decent one that I know of is a 300B amp from Elekit (you save a lot because it is a kit that has to assembled), but the other issue is that the 300B tube can be quite high in price.

you won‘t actually damage the speakers with a single ended 300B tube amp unless you are a complete bonehead. They soft clip and sound so flabby and out of control when right over the limit you won‘t want to be listening to them.

The dramping factor of your amplifier and how that equates to an overal system damping factor inc the impedance of speaker cables can also become part of the equation, usually higher DF the better.

good rule of thumb, but things get a little bit more complicated with high sensitivity full range drivers (don‘t they always) as this article by Nelson Pass will explain:

https://www.firstwatt.com/pdf/art_cs_amps.pdf

Klipsch is fine to try out higher sensitivity but it's near equal to dipping a toe in a hot tub. So if this combo is not to your liking don't judge all higher sensitivity loudspeakers saying you explored them you just tried a wee taste of what they can do.