I wasn't talking about the speakers, but the head-unit itself. This is often not just a radio, but an integrated unit with display, controls etc for navigation,

I wasn't talking about the speakers, but the head-unit itself. This is often not just a radio, but an integrated unit with display, controls etc for navigation, radio, HVAC etc. In just about any car produced >2000 these radios are integrated in the dashboard, thus not easily replaceable.