Opps, that grey box was the cruise control unit. I found the Clarion amplifier behind the rear passenger back seat, in the trunk. It was on the
other side
It has 2 looms going into it, and from the schematics I figure that they are for the front and rear amplifer.
Edit: - I've just checked the electrical wiring for looms B114 and B115. I now know exactly where my inputs are, where my outputs are, and how to wire it up. I'll be listening to music during the weekend