The Maserati Biturbo has been constantly evolving, making it difficult to keep track of all its changes. The first was the S (1983-1985), presented in Rome on 23 July 1983 and distinguished by its two-tone paintwork and seats designed by Missoni in Jacquard fabric. Its suspension was lowered, its Pirelli P7 tyres were wider and its 2-litre V6 was increased to 205 bhp thanks to the air/air exchanger, a significant increase in power. The ES (for Export) version was offered in 1984, still with a 2.5 but with only 196 bhp because it was catalysed for the US market. The second series of the S Biturbo was introduced in 1985, with a few minor updates, and became known as the Biturbo S II. A slight increase in power (+5bhp) improved acceleration figures, while the larger fuel tank (80L) allowed for greater range.