Thinking of putting in an aftermarket player

[VooDooCC]

Nothing wrong with the one I have, just want to stream music through bluetooth. I was shopping around at Crutchfield, but they say I need an adapter they call a 4 line output converter. Thing is, they don't ask about what the stock system is, so I'm just wondering if I need this. Thinking I read about looking under the driver's seat for an amp. I have some kind of box under there, with some wires going to it, would this be it?

I have an '09 LX V6 4x4. Here's a link to a used one at a dealership that has the same stereo I do if that helps.

Do I need this adapter, or is there a way to bypass the amp? Also, my back speakers are already really quiet, even when I adjust the fade to all rear. Sitting in the back it doesn't even sound like they are there.

Thanks,
Justin

[mkthshk8871]

Last year i took out my stock unit and replaced it with a Double din JVC unit. i had to trace the wires to the amp to see which ones i needed to use, i could find the right aftermarket factory wiring connector.