Koenigsegg, the 20-year-old Swedish high-performance “hypercar” maker, does its own thing with product development, so it's probably good that the maker of slightly over 100 cars/year did not complete its attempt to keep the Saab name alive with a takeover of that marque's mass production facilities.

The company is back in the U.S. after a five-year absence, and featured the Agera two-seater in its return, in a display at the New York International Auto Show. The car, which has a carbon-fiber monocoque-type body, also uses the first carbon-fiber wheels certified for road use, and a host of other super-premium technology.

The Agera, which takes 4000 h to build, is not a racecar, although there is a configuration that could put it on the track. That version will be featured in a Koenigsegg exhibit at the upcoming Beijing Auto Show.

The "standard" R model has a rated top speed of 450 km/h (280 mph) in top gear. The tires are a special Supersport design developed in collaboration with Michelin, which rates them for over 415 km/h (258 mph).

The carbon-fiber wheels are 19-in front, 20-in rear and weigh just 5.9 kg (13 lb) and 6.5 kg (14.3 lb), respectively, which lowers unsprung weight. The brakes have ventilated ceramic discs at the four corners, with six-piston calipers in front, four-piston calipers in the rear. The 100-0 km/h (62-0 mph) braking distance is just 30.5 m (100 ft).

The company casts its own engine—a 5.0-L twin-turbo V8 that is rated at 1100 hp (821 kW)—and develops 90% of the parts in-house. The engine, which weighs just 434 lb (197 kg), is a dual-overhead-cam design, slightly long stroke—91.7 x 95.25 mm (3.6 x 3.75 in)—with multipoint injection, dry sump lubrication, and 1.3-bar (19-psi) boost pressure for the turbos. The intake manifold is of carbon fiber.

Koenigsegg does its own engine calibrations and has designed the "R" to be flex-fuel, operating on a range that includes premium pump gasoline and E85, on which it is rated at 1200 hp (895 kW). The fuel system has the flow capacity to be able to handle the varying requirements of different fuels.

The transmission, developed in conjunction with Cima, the Italian gear maker in the Coesia Group, is a 7-speed dual-clutch design, but is somewhat different from a conventional design. Koenigsegg claims very fast shift times. It starts with a twin-disc dry clutch, but inside the transmission is a hydraulic wet clutch that is engaged to slow the input shaft for gear change prior to the engagement of the synchronizers. An electrohydraulic shift mechanism acts directly on the forks, to reduce inertia. Power flow goes through to an electronic differential, built by Koenigsegg and with controls calibrated by the company's engineers.

The Agera has an easily detached one-piece top (carbon fiber like the rest of the body) that turns the car into a roadster. Where to store that top, as the front luggage compartment of the mid-engine car "obviously" is too short? No problem: the front luggage compartment has a slot-like section at the rear that enables the top to slide through to the underside of the dashboard.

The car is just 169 in (4293 mm) overall on a 104.8-in (2662-mm) wheelbase and has a curb weight of 1435 kg (3164 lb). Ground clearance is just 100 mm (3.9 in), but the Agera has an electrohydraulic system with actuators over the Olins dampers of the front and rear double-wishbone suspensions. That system, which operates at up to about 450 psi (31 bar), can increase the ground clearance about 50% for public road operation.