you will need what is called a line tap.... its a small box that fits behind the radio. it taps into the rear speaker wires and allows you to plug the RCA and remote wires into it... I used one of these in my truck because i wanted to keep the factory look.. eventually i put in a new alpine cd played it had much better sound and even looks so personally i would reccomend a new head unit and not using the factory radio if you want better sound that is....with the line tap you would be sending rear speaker sound to the sub, but with a head unit that has a sub output you would be sending subwoofer sound to the sub..... hope this make sence....