The mighty Porsche 956 was the creme of the field in the 1983 World Sportscar Championship, and the works Rothmans-backed team was the one to beat. Despite impressive challenges from Lancia Martini and the privately-entered Porsches of Joest and Kremer, the down-to-the-wire championship battle would be between works Porsche drivers.   In this review we head to Round 2 of the series at Silverstone.