A Koenigsegg is built on the same principles as a Formula One racing car; a mid mounted engine bolted to the chassis, covered by a carbon fibre body. The chassis incorporates a semi monocoque, a self supporting unit made of carbonfibre and aluminium honeycomb, which both protects the driver and provides superior rigidity. Koenigsegg’s goal has been to create the perfect machine for speed. This has meant that the engineering team has had to focus on reducing weight to a minimum. Turning to the aerospace industry for the latest materials and technologies, they have produced a monocoque unit weighing only 62 kg, while the fully equipped car is as light as 1180 kg.

Both the body and chassis are made of a laminated composite of carbonfibre and epoxy. This material is five times stronger than the same weight of steel, and it is completely resistant to corrosion. The Koenigsegg semi monocoque is a sandwich construction, built up of 21 layers of carbonfibre, including both unidirectional and woven material. The sheets of carbonfibre are pre-impregnated with epoxy, a method that speeds up the laminating process and provides unequalled rigidity, and also it decreases the weight of the final construction.

Moulded into the Koenigsegg monocoque is a layer of aluminium honeycomb spacing, which is the key to its unequalled strength and lightness. This technology is used in Formula One and Cart Cars, but in no other streetcars currently in production. The aluminium honeycomb is also used for safety reasons, since it is a great material for absorbing impact force in a collision. The carbonfibre parts are cured in an autoclave, an oven for heating composite material under vacuum-pressure, which is necessary to achieve the desired strength of the chassis. The monocoque has been evaluated by the University of Lund, and found to have a torsional rigidity of 28.100 Nm/degree, which is superior to that of any competitor.

The chassis consists of three modules; in front, a lightweight steel subframe forms a compact package that contains the power steering components, the CrMo wishbones, the anti-roll bars and shocks, and also leaves room both for the stowable hardtop and an unusually large luggage compartment. The CrMo subframe is mounted onto the centre monocoque module. The rear subframe unit includes the entire drive train, which is assembled separately and then bolted to the monocoque. Its main parts are the twin milled aluminium alloy brackets that support the CrMo wishbones and the Cima gearbox. The brackets, which are lightened using the latest computer assisted tools, are held in place by CrMo rods to ensure perfect rigidity.

In the process of developing the chassis layout much effort has been laid on perfecting its weight distribution. The final solution is in itself an engineering marvel, with a weight distribution that borders on perfection: 43/57% - f/r. All high density components are centred around the cockpit (engine, occupants, fuel tanks and batteries), giving a low polar moment of inertia and very quick reaction to directional changes.

The modular solution for joining the monocoque and rear subframe was chosen by Koenigsegg over other, simpler solutions. This type of chassis was developed for Formula One race cars, and has the advantage of both maximizing rigidity and minimizing weight. Other designs chosen by competitors must, by default, be weaker and heavier than this solution. Koenigsegg's modular system also has the benefit of great accessibility, enabling quick repairs during racing and easy maintenance for everyday road use.

The noise from the engine has been neutralized by the Koenigsegg engineering team through the development of special insulating materials, which hinder vibrations from transplanting through the subframe fix-points into the cockpit. This has as quiet a cabin space as possible, with the use of only 35 kg of noise reducing material.