Complex sentence: The vehicle was only produced for two years (1964 and 1965) and only 502 Stellinas were made, nevertheless marked an important step in the development of new technology for Fiat, the Italian and perhaps even the global automotive industry.
Split into simpler sentences: The vehicle was only produced for two years (1964 and 1965) and only 502 Stellinas were made. Nevertheless, the model was an important step in the development of new technology for Fiat and the rest of the automotive industry.