The research, aimed at defining two- and four-door variations for both versions, was destined exclusively for the Brazilian market. The three-box, two-door Uno went into production in March 1985 under the name of Premio. In January 1987 it was decided to export the four-door version to Italy, called Duna. Giugiaro found himself in the position after more than two years of having to do additional work on one of his favorite creations: the Uno. As he has affirmed many times, he didn't like these transformations from two to three boxes when the original was already in production, and therefore untouchable up to the rear door.

Giugiaro had undergone "training" with the "Tipo 4" models and the Isuzu Gemini in the design of one-, two- and three-box models using the same sheet metal. Here also he sought to differentiate as far as possible between the two cars. In the two-box version he expressed a theme that he was fond of, the side with three windows, while for the more classic sedan, he chose at C-pillar in sheet metal.

Called Excel on the domestic market and Pony or Pony Excel for export, this car was to be Hyundai's key to the United States market. Almost 200,000 units being sold in its first year, 1986, it was to set an all-time record as the most sold imported car for its first twelve months of sale. Nine years after the design of the first Pony, Giugiaro was finally given "carte blanche", furthermore the technical structure of the Korean manufacturer had evolved and was now able to transport the designer's proposal into production.

The construction of this prototype was finished at the end of July 1985 and after a brief period of road trials to set the suspensions and the turbocharger pressure (it boasted a Ford V6 3-liter twin-turbocharger), it was sent to Ford in Dearborn. Slight, but substantial overall, the design differences between this road trial prototype and the prototype presented at the 1984 Turin Motor Show.