High-performance model had the most improved fuel-economy over its official rating at U.K. event.
The Vauxhall VXR8 has won the title for most improved fuel-economy at the Fleet World MPG Mararthon in the U.K.
The VXR8's set a fuel-economy rating of 32.14 miles per gallon (imperial) which translates into 8.79 liters/100 km from a combined official rating of 21 mpg (13.45 liters/100 km) - an improvement of 53 percent.
The car was driven by Chris Mooney, editor of Top Gear Online, with navigator Andrew Duerden from Vauxhall assisting. The event took place over two days and covered 350 miles on various routes including A and B roads as well as motorway driving.
"Andrew and I are, as they say, over the moon to win the overall best percentage improvement in the VXR8," said Mooney. "It just goes to show that the person behind the wheel can make a massive difference to fuel costs and carbon emissions. And, of course, that a 6.2 litre V8 is a very sensible choice of engine in the right hands."
The VXR8 features a 6.2 liter LS3 unit with an output of 431 PS (317 kW) and 550 Nm (406 lb-ft) of torque.