La vettura fu progettata a partire dal telaio della Fiat Punto con passo accorciato ed ... Fra le sue caratteristiche costruttive principali, il variatore di fase (VFD)....
Referring to the Barchetta, this (Google) translates as:
The car was designed from the chassis of the Fiat Punto with a shorter wheelbase and ... Among its main design features, the variable valve timing (VFD)....
So, there you go. You learn something new every day. (And then I forget most of them....)