I’m looking at a Metris that has what I want ...except....it has the basic AM/FM radio, and I would like something like the AM/FM/CD changer I have in my GL 450. How hard would it be to pull out the old one and install what I want? Is this audio set up the W164, W201 or W203 variant? Sorry if the question(s) are dumb....I’m not THAT handy, but looking for help getting started to do this myself, if possible. Thank you!