What is this wire harness?

[homeroom1]

Hello,

I'm in the process of installing an additional amp so that I can power 2 10 inch subs. I've powered the sub but am now trying to find the appropriate speaker inputs.

I'm driving a 2006 X5 (E53) 4.4 with DSP. There is already an amp and the factory subs which I have now disconnected.

In the battery compartment I found a connector labeled "amp" which is not connected to anything. I've attached the pictures of the plug I have found.

*If this is NOT an additional pre-amp can anyone tell me the color of the wires going into the existing amp that correspond to the various speakers? ie: left front, right front, left rear, right rear

Thanks,
Chris