CHICAGO – Early February in The Windy City seems like an odd time to unveil a convertible.

But winter makes no impression on Jaguar Cars North America, which debuts what it calls the most-powerful street-legal convertible ever – the 550-hp XK-RS concept car – here at the Chicago auto show.

Developed by Lansing, MI-based Rocketsports Racing and Jaguar, the XK-RS is based on the British auto maker’s XKR sports car. XK-RS is powered by a souped-up version of Jaguar’s AJ-V8 Trans-Am engine.

“This is the ultimate XKR – a beautiful car that goes really, really fast,” says George Ayres, JCNA vice president-marketing. “And although there are no production plans for this particular concept, the design is very likely to influence future production cars.”

Rocketsports increased the engine’s displacement from 4.5L to 5L, and an Eaton supercharger was installed. Top speed is 200 mph (322 km/h), and the XK-RS will go from 0-60 mph (97 km/h) in less than four seconds.

The standard 6-speed ZF automatic transmission was replaced with a 5-speed manual transaxle. Driveline weight was repositioned for better mass distribution, special underbody air tunnels running the length of the car were created, deeper front and rear spoilers were added and wheel arches were widened.

The production XKR’s modified suspension offers coil-over Penske shocks. The cabin features black leather seats with medium gray inserts. XK-RS’ exterior is covered in black lacquer. A lunging Jaguar graphic adorns each side, stretching from the rear wheel well to the A-pillar.

bcorbett@primediabusiness.com