I don't listen at real high volumes, but I do like classical music at close to live levels.
Classical music can get to 115 db in the first 5 rows of almost any concert hall. To do that with your speakers will require over 1000 watts.
A nimble amplifier- now that is another matter. It would be great if power supply filter capacitance and power were all that you needed to know, but its way more complicated by that! The one thing you need to know about this as that you cannot look at the spec sheets made by anyone and get a clear picture of the amp which will have the fastest transient response.
One spec that points to that though is risetime or slew rate. A slow risetime is 15Volts/microsec, a fast amplifier is over 100V (our amps, which are tube, have a 600V/usec risetime in the output section). You will find also the the shorter the signal path is in the amp or preamp, that there is a loose correlation to the 'speed' of the amp.
Feedback in the amplifier will slow its response, though quite often at the same time will seem to make the amplifier sound brighter (due to the addition of trace amounts of odd-ordered harmonics). Its one thing to have speed, but its another for the price to be one of irritation, so this is an area of concern for any designer!
Consequently, this really becomes a matter of audition.