American firm Czinger has removed the roof from its 1250bhp tandem-seat hypercar – which can outsprint a Bugatti.

It claims the 21C Spyder generates the most downforce of any open-top road car, producing 1482kg at 150mph – or 1500kg with the roof panel in place.

The V8 hybrid is even quicker in a straight line than the Bugatti Mistral, taking 1.9sec to hit 62mph from rest, compared with 2.5sec for its W16-engined rival.

The 21C Spyder also introduces a new braking system, produced using the same ‘BioLogic’ 3D-printing technique as for its extraterrestrial-looking suspension arms and chassis braces.

This, Czinger claims, reduces unsprung mass while improving rigidity and cooling and reducing stopping distances by 15% compared with the 21C’s existing system. It's also said to reduces brake squeal.

The 21C Spyder is powered by the same 2.9-litre twin-turbocharged V8 as the existing 21C, which produces 750bhp on standard unleaded petrol. This is matched with two electric motors on the front axles and one connected to the crankshaft, which unlock the full output. 

Czinger said the 21C Spyder didn't require additional structural reinforcement to make up for the lack of a roof, because such a variant had been planned when the carbonfibre tub was originally designed. However, there is extra bracing in the A-pillars to provide greater roll-over protection.

This makes it only 10kg heavier than the 21C High Downforce coupé.

Prices start at $2.75 million (£2 million), although they will vary: each example will be personalised according to its buyer’s wishes. A total of 30 will be produced.