Audio Systems: 2007 Pacifica Subwoofer install, 2007 chrysler pacifica, chrysler pacifica

Question
Just purchased a 2007 Chrysler Pacifica. Has the top model oem head unit with DVD minus the sub (not Interezmo sp?). Can I drop a salvaged (or new) sub into the factory location? Will the appropriate connections be available.
Or if I were to buy a powered sub would there be wiring available behind the blank grille I can tap for signal (power would be routed independently)?
Thanks for any help.

Answer
I did this upgrade to my Fiancee's Pacifica, and luckily, I had a whole salvage car to pull from! What you really need is the Subwoofer AND the amp/brain that is mounted under the trunk floor, passenger side. The one you have looks the same, but has no sub amp output inside. The wiring was all plug & play after swapping the amp/brain unit. Check with an auto wrecker for both  parts. Or E-bay...