What are you looking for, Steve?
If you just pop the top off, I'll bet you can see who made it just by looking at the chips. Any Pioneer chips and you have your answer. I suppose you could also google to see who has an OEM division in Portugal.
The WIS has some info about the connectors. All the source signals come from the EHU. From the looks of things, the signals get divided/equalised in the EHU and the amp just amplifies the sounds. So, again, looks like no full spectrum available. If they are sending low-level signal from the EHU to the trunk via copper they should have used shielded cable. Does it look that way? Otherwise noise might creep in.