Has anybody used an aftermarket harness in a 2009/2010 with the factory navigation system to feed their aftermarket amp? I also have the factory SONY system with a sub currently in my Platinum.

I am looking to use a "T" harness to allow for installing a MDX RE Q5 sound processor for RCA connections to run to my 5 channel amp. I really would prefer to not cut the factory harness up and yet want to retain the stock head unit and all of the SYNC features. I am thinking the Metra BT 5520 might do the trick, but would like to make sure before I pull the dash all apart.

I know brn2yrd did it on his xlt, but he didn't have the navigation system in his truck. Here is his post on his install and what I am trying to replicate in my truck. Below are a couple pictures of the harness in question.

 

Take this with a grain of salt:

In my '08 I bought the wiring harness and the reverse harness and wired all the like wires together excluding the speaker wires. The wires coming out of your head unit would go to the re-q and the wires out to the speakers would have to be connected to the amp. Then obviously you run your patch cables to the amp from the re-q.
I'm not sure that this will be the same process for the newer trucks, just trying to give some direction. Hope this helped some.