adding a amp to shaker 500?

What color wire do you guys use from the factory stereo to get a good turn on lead remote wire? I want to add my amp and sub but I'm using
the factory radio. I already got the line converter for the RCA's. I have the Shaker 500. Maybe it won't really make a diffrence though. I dont want to add a aftermarket stereo because i like the 6 CD and MP3 feature on it.

Can any one help me with what options I have to wire my remote wire. Im not to familiar with sound system installation. Thanks!

I installed my amp last saturday. I took out my shaker 500 headunit and cut the ignition cable and wired my remote wire to it. The only problem is even if my stereo is off my amp will be on but i usually have my stereo on anyways. I added a kenwood 800watt maxx 460 rms when bridged at 4ohms. Sub i used was a kicker compVR 12 and wired it to 40 ohms. I was happy with the end results. Might have to add some dynomat now though.