1985 BMW stereo security wires

There are two wires (yellow and white, solid) coming out of the head unit that attach to a harness. This harness plugs into what I assume are two security wires (RED / green and gray/red). I unplugged the harness to see what would happen, and now you have to punch in the security code every time you turn on the radio. Obviously, I plugged the harness back in.

Do I need to bother with these security wires when installing a new unit?

"Newer is seldom better"

Reuben Paul    

Thanks. I'm still waiting for the new unit to arrive so I'm trying to get everything figured out for when it shows up. I wasn't aware that this car had a factory amp. Where is it?

The back of the factory radio doesn't tell me anything except for left & right speaker outs. Luckily, I can easily get to all the +/- speaker wires coming from the fader control (directly below the head unit).

It would be nice to know what exactly the RED / green and gray/red wires were.

There are 2 PURPLE / white wires going to a "12V" black box (constant or switched?) along with a brown wire (ground?)

There is also another plain white wire all by itself but next to the power wires. I thought this was the switched 12V wire because it seemed to head towards the ignition and wasn't bundled with all the others. Does anyone know what it is?

Finally, there are two BROWN / red wires connected to the male end of a harness but it wasn't plugged into anything what I took out the stereo. Any ideas?