Audi engineers have further advanced the development of the 4.0 TFSI engine for the new S8 plus. The sonorous V8 biturbo engine now has a power output of 605 horsepower (445 kW) and a maximum torque of 700 Nm; in overboost mode, it can even produce 750 Nm. The large sport sedan - whose power was boosted 63 kW (85 hp) compared to the S8 - accelerates from 0 to 100 km/h (62.1 mph) in 3.8 seconds, and its governed top speed of 250 km/h (155.3 mph) can optionally be increased to 305 km/h (189.5 mph).

Modifications made to the 4.0 TFSI range from its special engine control with speed and charge pressure boosting to its modified exhaust valves and the inner geometry of the turbocharger that was optimized for efficiency.

An eight-speed tiptronic distributes the forces that are generated by the power-boosted V8 engine to a quattro drivetrain with a sport differential. Chassis highlights include the adaptive air suspension sport and dynamic steering, both of which chassis experts tuned specifically for the S8 plus. In Germany, the car comes with 21‑inch wheels that were specially designed for the S8 plus and size 275/35 tires..