The Jaguar XJ-S was built from 1975-96 and was the most affordable mass-produced V-12 sports car ever built. But owners constantly balanced enjoyment and aggravation, which has depressed prices to bargain levels. Stiffer emissions and safety regulations demanded a new kind of Jaguar sports car in the 1970s.

By the end of 1984 the TWR developed V12 engines in the XJS were rated at approximately 336 kW (451 hp).

The Jaguar V12 was regarded as one of the premier power plants of the 1970s and 1980s. After launching the second generation XJ series in 1986, Jaguar developed their V12 into the racing engines that brought two overall victories at the 24 hours of Le Mans endurance races of 1988 and 1990.

More importantly, its Department of Energy fuel consumption figures are stated as 27.1 m.p.g. at 56 m.p.h., 22.5 m.p.g. at 75 m.p.h. and 15.6 m.p.g. for the urban cycle. The introduction of this revised V12 engine coincides with a major quality and reliability campaign instigated by Jaguar Cars Ltd.