Alfaman75: please post a scan of the article if you can.
If I was going to try and explain this car from a practical stand point I would say:
BMW had a Bertone 503 prototype/testcar/whathaveyou laying around and figured it would be unremarkable to see one of these rolling around, and to explain the obvious absense of a V8 exhaust note they stuck Alfa grill and badges on it. As I said in the first post, who would question the authenticity of a zippy custom Bertone built Alfa with a 4 cylinder engine, even if it bears a striking resemblance to a current Bertone bodied BMW V8 coupe. The perfect disguise really...
Anyone else care to speculate or provide some documentation?