How about this Autobild Sportscars article from October 2011. It features the then-developing RUF 911 Turbo PDK, the ABT Audi R8 GTR and the Vath Mercedes Benz SLS AMG.
It’s great to see so much diversity with the Europeans and their supersports cars. The Audi an AWD, mid-engine V10, the RUF an AWD, rear-engine Flat-6 biturbo and the Benz a RWD, front-mid engine V8.
I can’t read it, because it’s in German, but just looking at the acceleration figures, the RUF is leaps and bounds ahead of the other two. Even with nearly identical horsepower across all three cars, the 0-300 km/h is 10+ seconds faster than the next fastest car.
Click on the picture for a full-size readable version of each page.