Aftermarket headunit in mercedes?

I think you need a dash kit for that, and if there isn't one, its gonna have to be a custom install. As far as your cd changer your gonna lose that feature because its meant to work specifically with your factory radio. Your steering wheel controls however might be able to retain them, they do make adapters to work with factory controls and aftermarket stereos. As a matter a fact you might find one for the cd changer. Your gonna have to be prepared to drop quite a bit of green to get it done. It might be better just to leave the factory unit in