 The exterior retained the aluminium body panels of the XJ220 concept , but for the production vehicles , Abbey Panels of Coventry were contracted to provide the exterior panels . The scissor doors were dropped for the production model , and significant redesign work was carried out on the design when the wheelbase and overall length of the car was altered . Geoff Lawson , Design Director at Jaguar took a greater interest in the car and insisted the design had to be seen to be a Jaguar if it was to be successful in promoting the company . Keith Helfet returned to undertake the necessary redesign work mandated by the change in the wheelbase , which was reduced by 200 mm . The turbocharged engine required larger air intakes to feed the two intercoolers . Situated between the doors and the rear wheels , the air intakes were larger on the production version of the XJ220 than on the concept car . A number of small design changes for the body were tested in the wind tunnel ; the final version had a drag coefficient of 0 @.@ 36 with downforce of 3 @,@ 000 lb ( 1 @,@ 400 kg ) at 200 mph ( 320 km / h ) . The XJ220 was one of the first production cars to intentionally use underbody airflow and the venturi effect to generate downforce . 
