Also you won't notice the difference from 630w to 1000w rms. As power double there a 3db gain and increments of 3dB is what the human can notice when it comes to output.
And yo further more to reassure you. I was running 2 12 mojo with a 3kw rms amp at .5 ohm and it sounded nice and loud. I sold the sub and box to my cousin and he a cheap flea market 100w amp on it and it was just a loud, we'll maybe with 500w it would be a little more comparable.
If you care to learn please take everything with a grain of salt even vets here offer shifty info. I design, build and install and test my equipment in different orientation to actually learn.