Found this image of the unit I had (though this one is branded Marantz). The head unit also controlled a CD stacker that was mounted in the boot and had a matrix display.
As far as AM Stereo went it was excellent. The Medium Band Width setting was good at night when chatter from adjacent frequencies could spoil even local strong stations.
As well as AM Stereo it had Dolby B, C and dbx, Metal tape capacity, 7 channel equaliser front and rear. 12 FM and 6 AM pre-sets plus a separate memory that scanned and stored the strongest stations (good for trips).
I still have it and can get it running with a 12 volt amp.
Seems they were also used in Porche
