I have a very nice car subwoofer and a nice Cerwin Vega HT box. The sub can do 4 or 8 ohms and will be connected to a Yamaha 661 AVR. I would like to save myself the money for right now and use it if I could.

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=103707&d=1204526260
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=103708&d=1204526260

Now I have two of these and one is a DVC so like I said I can get 4-8 ohm load.

What amp will you be powering it with? I'm assuming you will run an LFE connection from your receiver, thus necessitating an amp to power the driver. In general, car subs don't do so well in an HT environment, but there's no reason why you couldn't use it. Head over to the DIY forum, you can probably get a lot more advice about that driver.

Are you using a sealed or ported box? Based on the back of the magnet on that driver, I'd assume sealed?

Car subs are generally tuned to a higher frequency than the usual home subwoofer. Not a good choice if you want DEEP bass IMHO.

Carefull selection is required, but yes. I'm building a sub for HT using an Ascendant audio Avalanche 15" which could be considered a "car" sub, but has a FS of 15.7Hz and so will go deep indeed!
Look in the "DIY speakers and subs" forum for a ton of ideas that with a little work (ok alot of work) that can knock the socks off of an "off the shelf" HT subwoofer.

Cool tTY I will go there now and see what I can find hehehe

When it comes to audio this guy says, never say never!!!.

Im running two cerwin vega 15 inch strokers wired up for 8 ohms each and powering both of them with its own dedicated amplifier. A cerwin vega cv 2800 on each driver bridged for mono output with 1800 watts power for each sub at 8 ohms.

These puppies are running in my 14 by 12 room. !!!! lol. SOUNDS FANTASTIC!. Goes real nice with the two Yamaha Yst SW 800s im already running.