The M5 CS leaves the factory with 627 hp (468 kW) and 750 Nm (553 lb-ft) of torque from the twin-turbo 4.4-litre V8. Power is sent to all four wheels via an eight-speed automatic transmission and the rear-biased M xDrive all-wheel-drive system.
The tuner can offer an entry-level GP-700 package that takes power up to 690 hp (515 kW) and 850 Nm (627 lb-ft) thanks to a software upgrade.
There are a few offerings in between but the beastly GP-900 package cranks things up to a whopping 887 hp (662 kW) and 1,050 Nm (774 lb-ft). This immense power was achieved with upgraded turbochargers, sports downpipes, and the Deeptone exhaust system.
Cosmetically, the only changes are the forged wheels and 100mm tailpipes available in carbon or forged carbon.
As for pricing, the tuning packages start from as low as €2,495 for the software-only GP-700, but can reach €23,640 for a full-spec GP-820 (hardware, software, and visual tweaks) and even higher for the GP-900.