Subwoofer Install Questions/Help

Hi All,
I have a Infinity Basslink that I would like to hook it up to my Fusion (SEL w/Audiophile) and use the speaker level inputs again and just piggy-back off of the rear 6x9's.  First question, where can I run the power wire to get to the battery (is there a grommet in the firewall that allows for easy passage?)  I don't need to worry about the remote turn-on lead with this solution, thus it is my favorite solution!

Second question:  If the speaker level inputs don't work out, and I need to use the Line Level inputs, where would I tap into the remote turn-on source (I wanted to use the 12v plugs, but they are on all the time).

Here are the pictures of it:
http://i58.photobucket.com/albums/g264/plgtx/DSCF0282.jpg
http://i58.photobucket.com/albums/g264/plgtx/DSCF0283.jpg

TIA