You'll need to get an aftermarket harness that will allow you to plug in the aftermarket radio into the stock plug. you will have to connect this wiring harness to the harness that goes to the back of the radio. you should be able to find this harness at any car audio place, and they also should have it at walmart. make sure you buy the one for your car. you'll also need an in-dash kit to install the aftermarket deck. actually, i'm not sure if you'll need this or if you can ISO mount the head unit. Most likely, the separates up front are going through the stock wiring, especially if they aren't amped. Might want to double check this though, you should be able to tell through behind the dash. Typically, the wiring harnesses are made by Metra and/or Scosche.