i agree withtheir opinions 5star....

your amp isnt capable of giving you 1K of power in real-time but its able to give you a decent amount...and if you already have it, might as well use it

there are several ways of plugging in your sub, below are among other available options
a. if youd like 2 subs for your low-end, you can procure 2 subs with dual 4-ohm voice coils and have em run each at 2 ohms by wiring each driver in parallel thus ending up with 200 wrms for each driver
b. or have each sub wired in series (8 ohms + 8 ohms)...then plug it parallel to end up with a 4 ohm load, giving you a 400 total wrms output
obviously config a is the simpler way to wire your sub-system

however, if it were me (and thisis just a suggestion) id get a single 12" sub and put it in a ported box, run it in mono...and enjoy the music
if youre really thinking of 2 subs, you may want to go smaller (like 10") to get your recommended ported box volume
and, believe me, 10s in the right box with ample juice is no pushover...besides itll cost cheaper and its usually easier to power
in my experience, a sub will only sound how its supposed to if you drop it in the right box, power it appropriately and make sure that your car can sustain that power

affordable sub choices i can think of for a 1 or 2sub system (that i was able to use or hear): JBL GTOs, Infinity Reference, Phoenix Gold RSD,old JL 12W0s, DDs (entry level subs)

hope this helps