1,1 HP per litre? This figure in relation to a high performance sports car such as the new ACS5 Sport Touring based on the BMW M5 certainly doesn’t refer to the conventional ratio of capacity to power. Instead: 500 litres luggage space meet 552 red-hot HP (406 kW). Plenty of room in every respect for incomparable driving pleasure on one hand, and a hang-glider, surfboard or mountain bike on the other. Drivers of vehicles like this think in different terms from conventional sports car drivers. But no way do they lag behind when it comes to driving dynamics.