Here comes a showdown between two of the moment's maddest family muscle cars: the Audi RS4 Avant and the Vauxhall VXR8 Tourer. The Audi RS4 Avant is powered by a 4.2-liter V8 engine that sends 450 hp and 430 Nm of torque to the quattro all-wheel-drive system. The RS4 Avant goes from zero to 62 mph (100 km/h) in 4.7 seconds. The Vauxhall VXR8 has a 6.2-litre V8 that's good for 431PS and 550Nm of torque. It can reach 60 mph in 4.9 seconds.