Now it's possible to go one-third the speed of sound, topless, with Bugatti peeling back the roof of its iconic A$3 million Veyron supercar. The new Bugatti Veyron 16.4 Grand Sport is a targa-topped version of the 746kW quad-turbo, all-wheel-drive wonder car, which boasts a top speed of 407km/h.

The open top car will be officially revealed on August 16 at the Pebble Beach Concours d'Elegance, with the first production vehicle being auctioned off at the event. Pricing for the new Veyron hasn't been revealed.

Although details are scarce - Bugatti is waiting until launch to reveal more - it is known that the targa-style roof is transparent and lifts out of the car. It's not known whether there is storage for the roof in the car, or whether it has to be left at home.

Other changes include strengthening of the structure to compensate for there being no integrated roof, as well as daytime LED running lights. The air intakes have also been altered to compensate for the different aerodynamic characteristics of the open-top Veyron.

The number being built is also up in the air, with Bugatti unable to provide details at press time. Bugatti has said that it will build a maximum of 300 Veyrons and as of March 2008 had sold 220 examples, two years after the car was launched.

A single Bugatti Veyron 16.4 was bought into Australia in March of this year. It was demonstrated at the Melbourne Grand Prix and shown at the Melbourne Motor Show, but being a factory demonstrator it was returned to Bugatti headquarters in Molsheim, France, once its public duties were finished.

The Veyron is only built in left-hand-drive, limiting its appeal in the Australian market. Left-hand-drive cars, unless they are classics, can't be registered and driven on Australian roads. Sales and distribution of the Bugatti Veyron are handled by Trivett in Australia, which is in discussions with two parties about possible sales of the supercar.

The open top Bugatti Veyron 16.4 Grand Sport isn't the first special edition that the company has built. Three other special editions have been made, including the Bugatti Veyron Fbg par Hermes, a collaboration with the French luxury goods maker Hermes, as well as the Pur Sang, which was delivered "naked" in its original material finish of carbon fibre and aluminium, and the Sang Noir, which was entirely black, with a tangerine interior. The Bugatti Veyron 16.4 Sang Noir was launched last month.