The Koenigsegg CCX is a mid-engined roadster from Swedish car manufacturer Koenigsegg. The CCX has been engineered to comply with the U.S. regulation and market demands and is a newer design that replaced the Koenigsegg CCR. CCX is an abbreviation for Competition Coupé X; the X commemorating the 10th anniversary, (being the Roman numeral for ten), of the completion and test drive of the first CC vehicle in 1996. The CCX was first unveiled on February 28, 2006 at the 2006 Geneva Motor Show although its existence was announced earlier. A derivative known as the CCXR is available, the main difference being that CCXR's engine is tuned to run on biofuel. The different fuel and tune allows the CCXR to produce 25% more power than the CCX.