Adding Amp and Sub to 09 Nissan Rogue w/Bose

Hey All,

I've poked around a little bit trying to determine the best approach for adding a sub and amp to my girlfriends 09 Nissan Rogue.  It is a lease so she doesn't want to put too much in it (i.e. my suggestion of completely removing all bose equipment). 

I am giving her an old RF 500a2 amp and a 12" infinity sub.

My question is how to tap into the bose system.  I realize that the Bose HU sends a balanced signal to the amp in the rear.  I discovered that there is an additional amp for the factory 6.5" sub.  I'm guessing that the line from the Bose speaker amp also sends a balanced line to the bose sub amp after it is crossed over.  I've included some pictures below, hopefully they will help.

Here is a close up on the factory harness before the sub amp:

If you look at the connector from the harness side (clip facing up as shown), the pin numbers are marked as follows:

2 | 4 | 6
----------
1 | 3 | 5

1 = Brn = Audio signal -
2 = Yel = Audio Signal +
3 = Braided (black) = Shield for audio signal
4 = Grn = Amp ON Signal (12V switched)
5 = Black = Ground
6 = Blue =  Battery +12V (fused at 10A)

Here are my current thoughts for a setup, but please, provide any insight:

Use the RF Amp and install LOC in between factory sub amp and sub.  Or I beleive my amp has speaker level inputs? Could/should i use those instead or is a LOC a better option?  I picked up a cheapy LOC from best buy.  Is there a better one suited for this application?

Thanks in advance!

**I pulled the pics from the nicoclub forums.  Thanks to users philipa_240sx and rogueagent08 for the info.