The Jaguar XJ-S (later called XJS) is a luxury grand tourer manufactured and marketed by British car manufacturer Jaguar Cars from 1975 to 1996, in coupé, fixed-profile and full convertible bodystyles. There were three distinct iterations, with a final production total of 115,413 units over 20 years and seven months. Originally developed using the platform of the then-current XJ saloon, the XJ-S was noted for its prominent rear buttresses. The early styling was partially by Jaguar's aerodynamicist Malcolm Sayer—one of the first designers to apply advanced aero principles to cars—however Sayer died in 1970, before the design was finalised. Its final iteration, produced from 1991 to 1996, was manufactured after Jaguar was acquired by Ford, who introduced numerous modifications – and eliminated the hyphen in the name, marketing Jaguar's longest running model simply as the XJS. Pre-HE (1975–1981) The XJ-S was introduced on 10 September 1975. The design and development had begun in the late 1960s by the code name of project XJ27, with an initial shape penned by Malcolm Sayer, but after his death in 1970 it was completed by the in-house Jaguar design team, headed by Doug Thorpe. Power came from the Jaguar V12 engine with a choice of a manual or an automatic transmission, but the manual was soon dropped as they were left over from V12 E Type production. V12 powered production automobiles were unusual at the time; Italian luxury sports car makers Lamborghini and Ferrari produced such models. The specifications of the XJ-S compared well with both Italian cars; it was able to accelerate to in 7.6 seconds (automatic models) and had a top speed of . The first series of XJ-S cars had a BorgWarner Model 12 transmission with a cast-iron case and a bolt-on bell-housing. In 1977, General Motors' Turbo-Hydramatic 400 transmissions were fitted. The TH400 transmission was an all-aluminium alloy case with an integrated non-detachable bell-housing. The XJ-S was originally supplied with Dunlop SP Super E205/70VR15 tyres on 6K alloy wheels; British police upgraded their Jaguars to a higher-performance 205/70VR15 Michelin XWX tyres. At the end of the 1970s Jaguar started to fit the 205/70VR15 Pirelli P5. The Pirelli P5 was the tyre that Jaguar had asked Pirelli to produce to improve their luxury cars. Jaguar launched the XJ-S in the wake of a fuel crisis, when the market for a 5.3-litre V12 grand tourer was small. The buttresses behind the windows