The new F10 M5 did not impress with its driving characteristics. Car and Driver stated the vehicle was very heavy in the 4400 pound range which quickly overwhelmed the tires. The steering was said to be numb but the car did post a respectable laptime which Car and Driver attributed to the power.
The F13 M6 was stated be incredibly similar to the F10 M5 although it is 206 pounds lighter. Car and Driver did not really like the M6 either complaining about the heft and rear end instability.
The Audi RS5 actually outlapped both of the previously mentioned BMW M cars despite the large power disparity. It even improved upon a V8 R8 previously tested.
The full laptime list and video for the LL3 class is below. Congratulations to Mercedes-Benz who had the fastest laptime of the class courtesy of the C63 AMG Black Series Coupe, very impressive: