Re: audio help?
Well, you have two routes you can take. You can go to your local car audio dealer and ask them for the installation kit and wiring harness for your model year and that'll make it a breeze, or you can start hacking wires, blow fuses and have a 10 min job turn into a 10 hour job. I would suggest you do the former because all you have to do is match the colors from your new stereo to the colors of the wiring harness.
If memory serves, if the '02 has two separate units (Radio and CD player) you remove both and put a pocket in the lower area. If it's a double din (I can't quite recall when they switched from a two din configuration to a double din config) configuratiion, the kit will provide the pocked and a place to hold the radio. It shouldn't be too bad, but if you have any other questions, feel free to ask.
Oh, just so you know, you're taking a high-output head unit and feeding it into factory amplifiers so you may not be able to turn it up too loud. Make sure you hook up the remote turn on (typically the blue or blue/white wire) to trigger the amps to turn on. Be careful NOT to use the power antenna lead because that will turn off when you switch from radio to cd and your amps will turn off.