I'll add some personal experience to my earlier comment. During the 1990's I was using 90db speakers having easy to drive impedance characteristics. In addition to some high powered solid state amps, I also used several different high quality vintage tube amps in the range of 20W to 60W, including Marantz 2's and 9's among others. This was in a 22 x 13.5 x 8 room, with a listening distance of 11 feet.
Recordings having either narrow or what I would characterize as moderate dynamic range, including many symphonic recordings, could be played with any of those amps at much louder levels than I or most people would want to listen at. However, occasional brief peaks on many symphonic recordings on labels such as Telarc, Sheffield, Reference Recordings, etc., could easily clip the amps that were in the 20 to 30W range. Using the Marantz 2's in triode mode (about 20W, from push-pull EL34's), a few recordings could actually arc the tubes, producing a bright blue flash.
So I guess the bottom line is that you'll be fine with most recordings, but not all.
Regards,
-- Al