In spite of a fifth place scored at the South African Grand Prix at Kyalami, the PC3 was evolved into the PC4, which was much more competitive, allowing Watson to score two podiums in France and Britain.
Malia un quinto lugar logrado no GP de Suráfrica en Kyalami, o PC3 converteuse no CP4, que era moito máis competitivo, co que Watson logrou anotar dous podios en Francia e Gran Bretaña.