The RS4 has a monstrously powerful engine, but has also been stripped of weight. The bonnet, suspension and front wings are all aluminium. It weighs 1650kg; a BMW M3 Clubsport 1577kg, but the Audi has four-wheel drive and more space in its rear seats and boot.
The cornerstones of the RS4’s appeal are its engine, gearbox and drivetrain. Unlike in the last (Avant-only) model, there are no turbos. Instead, the RS4 uses a development of the S4’s 4163cc V8 with a new crank, uprated pistons and con-rods, a bigger exhaust and bespoke cylinder heads. It generates 414bhp at 7800rpm with a peak rev limit of 8250rpm. There is 317lb ft at 5500rpm, with at least 285lb ft available from 2250rpm; an RS4 produces more torque at 2250rpm than an M3 does at its peak.
There is a new generation of four-wheel-drive system that sends 40 per cent of drive to the front axle, 60 to the rear in normal conditions, but this can change by sending 65 per cent to the front or as much as 85 per cent to the rear.
This system works in conjunction with the electronic brakeforce distribution program, anti-lock brakes, ESP and traction control. There are so many devices to keep it glued to the road, including four very wide and very sticky 255/35 ZR19in Pirelli P-Zero Rosso tyres, that it makes you wonder whether you could drive your RS4 across the ceiling.
The front brakes are 365mm ventilated discs with eight-piston calipers; at the back are 324mm ventilated discs and four-piston calipers.
The RS4 uses a system where the dampers are hydraulically linked diagonally across the car by a central valve to eliminate pitch, dive and roll electronically, but in as natural-feeling a way as possible. The RS also uses stiffer springs and bigger anti-roll bars than any other A4 and sits 30mm lower as a result.
Finally, there is a Sport button which enables a driver to select a more aggressive throttle mapping, a deeper exhaust note and even more bolstering from the seat.