The latest high performance variant of the SSC Aero made its debut at the 2005 Concorso Italiano in Monterey, CA. The car was specifically created to challenge the 250 mph barrier, and with recent top speed attempts by Koenigsegg and Bugatti, the car will have to achieve that number if it wants to hold the title of "World's Fastest Production Car". Following the creation of the 787 horsepower "Standard" Aero, the Ultimate version features enhanced body work with improved downforce at higher speed, as well as a more powerful version of the supercharged V8 engine in the standard car. An increase in boost, a modified cam, and an upgraded fuel delivery system help the engine make over 1,000 hp, topping the Bugatti Veyron. The car is also lighter by 200 pounds due to lightweight materials. The bodywork alone weighs under 150 lbs. The visual differences can mostly be seen in the rear of the car, which is sloped behind the cockpit and ends in a small spoiler. Using the testing in the windtunnel, the 250 mph should be achievable if a suitable track can be found.
source:http://www.fast-autos.net/vehicles/SSC/2006/Ultimate_Aero/
