Though conceived by Jaguar engineers in their spare time, the XJ220 held so much promise that company executives elected to put it into production. Like those of previous Jaguars, the XJ220’s model designation was derived in part from its top speed of 220 miles per hour, the fastest of any production vehicle at the time. Its twin-turbo, 3.5-liter V-6 engine produced 542 horsepower. Acceleration from zero to sixty miles per hour took a mere 3.5 seconds. The declining demand for supercars during the 1990s assured that the market was quickly saturated and a mere 350 of the $678,000 exotic cars were produced.