With just a month to go before the Vauxhall Insignia makes its debut at the London motor show, we’ve got exclusive pictures of the hardcore Insignia VXR testing at the Nurburgring. Well-informed sources reveal that this black fastback mule version of the Vectra-replacing saloon has four-wheel-drive and a more powerful version of the 2.8-litre turbo V6 from the current VXR. We’re expecting it to deliver around 300bhp. Autocar understands that Nurburgring testing on the standard Insignia finished some months ago – and that the hotter VXR is now being prepped prior to its launch late next year. Vauxhall is disguising the VXR’s looks for now – hence the fastback bodyshell of this test mule. A senior source within GM reveals that the finished Insignia VXR’s styling will stay close to the muscular looks of the original GTC concept, which was shown in Geneva last year, except with four doors rather than two. There are still some visual clues as to this prototype’s performance prowess, such as the twin exhausts and slightly bulging wheel arches. On the continent, the Insignia VXR will be known as the Opel Insignia OPC. It uses the same turbocharged V6 engine as the Saab 9-3 Turbo X and we understand that it will also get its Swedish half-sister’s torque-splitting electronic rear differential, which distributes power between the rear wheels.With drive delivered by all four wheels, the top-spec Insignia should be far less ragged than the two-wheel drive Vectra VXR. Prices will be announced nearer the time, but ‘accessible performance’ is at the heart of the VXR brand, so be surprised if it doesn’t undercut the Volkswagen Passat R36 by a substantial margin.