Move over Bugatti Veyron - there's a new king of the road coming through - the Saleen S7 Twin Turbo, already clocked at 416 km/h, with more to come!

US specialist company Saleen has been around for some time now, and its latest 560 kW S7 Twin Turbo production model owes a lot to racecar development in terms of its styling and technology.

Already incredibly quick, the S7 is now available with a 'performance upgrade' option which boosts the 7-litre twin-turbo V8 to a claimed 736 kW, same power output as the Veyron.

In "standard" trim the Saleen is as quick as the Veyron from rest to 100 km/h , at 2.9 seconds - thanks to less weight - hits 160 km/h in six seconds, and runs on to a top speed of 384 km/h.

However the power boost cuts the acceleration time down even further, while insiders say the car has already topped 416 km/h, with more to come.

By comparison the Bugatti Veyron, which until now has claimed the title of the world's fastest production car, is electronically limited to 400 km/h, although its designers claim it could go on to 450 km/h without limiters.

With 75 examples of the S7 already delivered in the US, the Saleen certainly has every right to take away the Veyron's title.

In standard trim the Saleen S7 Twin Turbo costs the equivalent in its home markets of R3.5-million, with the upgrade around another half million.