Hi Olaf,
never heard of a Conrero Zagato. Virgilio Conrero was famous for the Giulietta Engines and the first TZ's, but later I heard, he was working with Opel Engines, cause Autodelta took over. Never heard even of a Conrero prepared GTA. There seems to be one 2600 SZ, which was prepared by him.
The newer 105 Cars, were mostly from Autodelta, or Facetti.
But the Names Bosato, Facetti, Conrero and Autodelta, are good, to push the price up.
and the man died some years ago, so none could ask him.
Maybe some Conrero Cams, make a whole Car?
Regards
Jörg