Some things about amps definitely matter. You want an amp that can deliver the power your speakers demand. That's a function of their sensitivity and the impedance load they present. Every 100w amp isn't the same, because not every 100w amp can deliver those 100w with low distortion, and because not every 100w amp can handle sudden bursts of power or drops in speaker impedance.
Beyond that, however, amps are fairly similar. The best test is to get an amp into your system and see how it sounds--or, to be more precise, how your system sounds with that amp. Turn the volume up as high as you normally would, and see if you can detect any strain or distortion. If not, then that amp is probably good enough for your needs.
Beyond that, however, amps are fairly similar. The best test is to get an amp into your system and see how it sounds--or, to be more precise, how your system sounds with that amp. Turn the volume up as high as you normally would, and see if you can detect any strain or distortion. If not, then that amp is probably good enough for your needs.