This is the Aston Martin Vantage V12 prototype undergoing late-stage testing at the Nurburgring.We've already driven Aston's hardcore V12 concept car, but the iconic British brand is extensively trialing these pre-production prototypes, confirming that a showroom model is on its way.Sources close to the Aston Vantage V12 project reveal that the production model will retain the concept car's track-bred character in as pure a form as possible. Roadgoing production cars will have to be 'slightly sanitised', compared with the concept car, so that they can be homologated for real-world use. The range-topping Vantage 6.0-litre V12 engine is expected to produce around 550bhp when the car makes production, and our spy shots reveal that it has borrowed bigger carbon ceramics brakes from the DBS too.The engine hood is still aggressively vented to aid cooling. Visual changes include a newly designed carbon-fibre rear diffuser and different side rockers. But Aston plans to keep this limited-edition V12 model as enthusiast-focussed as possible. Less than 500 will be built.With development still ongoing, we won't see the V12 Vantage at the London motor show or indeed at any other this year. Autocar understands that the production model is being readied for early 2009.