You need:
When installing a new stereo in your car, your first step will be to remove the old stereo. Pay close attention to the steps involved, for the process for installing your new stereo will be the same, but in reverse.
Removing the factory stereo
For detailed information on how to remove the factory stereo in a specific vehicle, refer to your Crutchfield MasterSheet™ instructions, if available. They will walk you through the process step-by-step. Otherwise, you may use the general guidelines below.
Before you begin, start by setting the parking brake and removing the negative cable from the car battery to prevent accidently short circuiting something.
Your factory stereo will be mounted in one of two ways: 
Spring clip mounting
If the stereo is held in by spring clips, you'll need a pair of DIN tools. Insert the DIN tools into the holes on eitter side of the unit until a click is heard. The tools serve to release the spring clips and also hook onto the sides of the stereo so that you can pull it out easily. Spread the tools apart slightly then pull the stereo out of the dash.
Bolted in place
Sometimes, accessing the stereo requires the removal of one or more trimpanels from the dash. You may have to (carefully) pry the plastic trim away from the dash (which is often secured by hidden pressure clips), or locate and remove bolts to disassemble other pieces of panel. Once you have gained access to the factory stereo, removal should be obvious. The stereo will almost always be secured by four screws, sometimes bolted directly to the front of the dash, other times secured to side brackets. Remove the screws and pull the stereo from the dash.
American cars built before the early 1980s often came with a "shaft-style" stereo, which secured to the dash via nuts and washers to the right and left knobs. A shaft-style stereo must be installed from behind the dash. Getting it into position is the tricky part, since your vehicle's wiring, heater controls, and ductwork may be in the way.
Unplugging the factory stereo
If your vehicle has (or once had) a factory stereo, or if it was pre-wired with a "stereo prep" package, there should be at least one plastic wiring harness behind the stereo opening. This plug(s) connects the stereo to your vehicle's electrical system, and also makes the speaker connections. You will need to unplug the factory stereo from the wiring harnesses, and unplug the antenna to complete the removal process.
Car Stereo Installation Guide part 1
