aftermarket Amplifier 2002 Impala

Hey guys
Just wondering if anyone knew what the easiest way around wiring an aftermarket amp (for subwoofers) would be in a 2002 Impala. I know it has the factory one installed and I guess that I was wondering if I am still going to have to run RCA's, power, & remote or if I could pull the RCA connection and the remote off of the stock amp.

Thanks for any feedback
-Rick