I have a 2004 Malibu Maxx with a cd changer. I want to keep my oem radio/cd player but I want to install some aftermarket subwoofers in the trunk. I have a crossover for the subwoofers that uses a rca input from the stereo. Is there any way to hook this up without cutting any wires coming out of the radio or maybe a harness that can piggy back the oem one?

thanks