My next question was....... and now I see in the OP that I can answer my own questions........but i was curiousThe amp is only needed if you want to use a MAP radio. If you grab a PHONE button radio you can directly wire up.
I see a lot of Head Units (same as AU but have Volume and Tune Scroll buttons & knobs swapped LHD RHD variation), from the USA but dont think they would be region compatible. The ones that have PHONE and not MAP OEM from Subaru still have ACP AA MAPS built in. My Current MY17 has GPS MAPS and want the same type. Over here they are quite rare in wrecking yards so far.......... but this is a great project and I really want to keep the factory look.