By any standards this was a car of huge excesses: very powerful, very fast, very beautiful, and very expensive. It was high geared and somehow bulky, so even a millionaire would not choose it for everyday use, especially as it was strictly a two-seater and, frankly, hard work to drive.
The XJ220 was dreamed up by Jaguar's chief designer, Jim Randle The XJ220, unlike other supercars, was actually a spare time project - Jaguar engineers (secretly at first) started designing and building the car on the weekends.
The XJ220 first appeared at the 1988 Birmingham Motor Show.The original XJ220 concept featured a V12, unlike the twin-turbo V6 that was in the production car. Body panels for the XJ220 were made from bonded-aluminum honeycomb .Only 350 XJ220s were ever built. 
The original prototype of 1988 was only meant to be a one-off, and was even bigger than the production car which followed, using Jaguar's famous V12 engine, and four-wheel-drive. Although it had not even turned a wheel when exhibited, it carried the XJ220 title as an indication of its proposed top speed.
XJ220 a Saturday afternoon project that blossomed into one of the fastest road cars ever. It was eventually overtaken by the smaller Mclaren F1 but the Jaguar will never be forgotten for its size, beauty, phenomenal pace and grip. It has a 3.5 liter V6 engine with twin turbos producing 549 BHP at 7200 r.p.m. which can take the car from 0 - 100mph in 7.3 seconds.
The result was that only 271 cars were produced in three years, many of which languished un-delivered at Jaguar until the late 1990s. Amazingly, this supremely fast and beautiful Jaguar supercar now goes down in history as a commercial failure, tainted by the economic conditions of the day, rather than its own shortcomings.
Originally intended to be powered by a V12, Jaguar opted for a twin-turbo charged V6 which allowed a lower weight and smaller size. The 6.2 L V12 had been judged too difficult to get past increasingly strict emission regulations and there were also reportedly some design problems caused by the size of the power plant. It was replaced with a Tom Walkinshaw -developed 3.5 L V6 based on the engine used in the Rover Metro 6R4 rally car and fitted with twin- turbochargers , generating 549 bhp of maximum power at 7000 RPM and 473 ft·lbf of torque at 4500 RPM. This engine was not only the first V6 in Jaguar's history, but also the first to use forced induction . In spite of the smaller displacement and half the number of cylinders, the engine produced more power than the V12 would have. However, potential customers judged the exhaust note to be harsh and the lag from the turbos to be an annoyance. Also missing from the production version of the car was the Ferguson all wheel drive - the production car had only rear driven wheels, through a conventional transaxle .