for a musical system 1,000 watts is a waste-imho- you dont want the bass overpowering the music-, its also nice to have the same sonic signature with amps-
so no i dont think you will be under powered,monos only have about 30 more watts.they have tons of control over the woofers.
i use 2 of the inline things at partsexpress to work the cutoff-didnt like them at first ,now i think they work well-go figure

ive hooked the sub up in mono and run from one mono block
it was a little over powering and slightly louder (i dont have a seperate sub volume control) when run in stereo everthing is more equil.