The ACS5 Sport S is based on the BMW 550i model and dials up the noise on the 4.4 liter V8 to 540 PS (397 kW / 532 bhp) and 750 Nm (553 lb-ft) of torque from the series' 407 PS (300 kW/ 401 bhp) and 600 Nm (442 lb-ft). The 0 to 100 km/h sprint takes just 4.5 seconds and top speed is 320 km/h (198 mph).
AC Schnitzer works the same tuner magic on the Z4-based 99d to which it adapts a conversion kit inspired by the 320d Efficient Dynamics edition. The 2.0 liter diesel power plant is good for 190 PS (140 kW / 188 bhp) and 420 Nm (310 lb-ft) of torque with a 0 to 100 km/h sprint time of 6.9 seconds and a top speed of 235 km/h.