i've heard a 10w7 sound perfect off a 600 watts
i've heard a 12w7 sound perfect off 500watts, however i think 800-1000 is recommended
i've herad a 13w7 off 1k and it sounded nice too....
for a 10w7 again, i think 550-650 watts @ 3ohms will be perfect for it
all these were in a sealed inclosure (of course i've heard them in ported, but i'm just telling you how the sealed sounded so that u'll know what u'll at lesat have to have to make them pound)