you really don't want to exceed 60 watts RMS. that's a continuous max thermal power rating. more power than that nd you stand a good chance of toasting the speaker coils. now if you use a 104 watt amp on those speakers and never turn the amp up all the way (full volume) you won't ever send the whole 104 watts to the speaker and you'll be fine. it's just a matter of not overpowering the speakers and causing thermal damage.
hmm ..i have question i got like one amplifire and i got 2 speakers i wanna pu one more to the same amp.... wat i have to do.....and can i do that...????my amp got just to out put for 2 speakers.....so i dunno can some one help me...plzzzzz....
entirely depends on the load each sub presents, and to what load the amp is stable, but usually yes. if you'll see any increase in SPL is another issue entirely.