You would need the power inverter to run the car audio amp. Your sub output on your receiver should have a level control that you could use to set the volume. The actual subs should work pretty well in HT applications as they tend to go a little lower than a lot of car audio subs which tend to rolloff at about 60 hz.
I'll see if I can find an inverter somewhere that you could use. The limitation would be the expense because it'll likely cost you more than buying a couple of plate amps to power the subs. You could sell the rockford amp and pick up two 250w plate amps for about 250.00. They have become pretty cheap. If you need some help with the sub enclosures, let me know and I can make some recommendations on size.
What model subs do you have, dual 6 ohm, dual 4 ohm?
