to the forums,
Not quite sure of your question, but the cd changers that work with the factory "cd-ready" cassette players are either Alpine or Pioneer, depending on year of the car. Second pop your trunk lid and look on the trunk arms, there should be a sticker saying Prewired for CD Changer or something to that effect. There is an adapter you will need if you buy an aftermarket to make it work with you factory deck.
Buy an FM modulated cd changer. You can tune your radio to a station (89.7 for example) and the radio you have thinks you have a radio station on that chanel but your cds are playing on it.
My choice, buy an aftermarket indash cd player. You get way more features, power, sound quality, etc. in an aftermarket than you EVER will in your factory. It'll make even your factory speakers sound better with the improved power going to them.