The Stuttgart 455 RS6 is a race derived production car with immense cornering Gs, a revvy naturally aspirated engine and brakes that can shift internal organs if not handled with care. The engine is a 4 litre naturally aspirated flat-6 that revs to 9000RPM! The engine produces 460 horsepower and 420NM torque. The throttle response is instantaneous with individual throttle bodies and a high-airflow manifold. The engine block is also made of magnesium for weight reduction purposes. The aero on the car produces a peak downforce of 600KG (1,320 pounds). This combined with carbon ceramic brakes (massive 400mm in the front, 360mm in the rear) means that this will easily outperform a top-trim SBR4 by a large margin on the track.
Here is my YT video on the the creation of the vehicle and testing it: