window over the engine. The CCX has frontal area of and a ., with a CdA of . It also has a flat underside with venturi tunnels at the rear and an optional rear spoiler to improve downforce. At there is of downforce over the front axle and over the rear. The car is longer to comply with the US rear impact regulations and to free space around the rear muffler. On the interior, there is of extra headroom as well as specifically designed Sparco carbon fibre seats. Wheels and brakes First in the industry carbon fibre wheels are optional equipment, lighter than the standard forged alloy telephone-dial wheels, both using centre locking nuts. Diameter is 19 inches at the front and 20 inches at the rear equipped with 255/35 Y19 front, 335/30 Y20 rear Michelin Pilot Sport 2 tyres, 8 piston caliper carbon ceramic brakes measuring in diameter at the front and 6 piston caliper at the rear are optional, saving another of unsprung weight. Variants CCXR The CCXR is a more "environmentally friendly" version of the CCX, powered by the same engine, but converted to use E85 and E100 ethanol fuel, as well as standard 98 octane petrol. The CCXR required modified fuel injectors, upgraded fuel lines and piston rings, and a higher boost setting on the superchargers. In standard form, bodywork of the CCXR features heavily optimized aerodynamics, along with optional diffusers to enhance airflow, including an optional front splitter with an aerodynamic nolder. When run on ethanol, the power increases to at 7000 rpm and of torque at 5600 rpm. This is a direct result of the cooling properties of ethanol in the engine's combustion chambers along with the added boost, made possible by ethanol's higher octane rating when compared to gasoline. Due to the lower specific energy content of ethanol, the CCXR burns slightly more fuel than the CCX with a combined fuel consumption of under the EU cycle. CCX Edition, CCXR Edition, CCXR Special Edition At the 2008 Geneva Motor Show, Koenigsegg presented two special edition models, the CCX Edition and the CCXR Edition, both fitted with a remapped, 4.8 L twin-supercharged V8 engine and limited to 2 and 4 units respectively. The modifications to the engine increase the power of the CCX Edition to on normal gasoline and of torque while the CCXR Edition ratings remained unchanged over the CCXR. The Edition models