German tuner GAD has released an upgrade program for the Mercedes-Benz CLS 63 AMG. The most powerful CLS 63 AMG is the one fitted with the optional AMG Performance Package that lifts output to 558 HP (410 kW) and 799 Nm (590 lb-ft) of torque. If this isn’t enough, GAD can increase the engine output to an impressive 803 HP (590 kW) and 1149 Nm (847 lb-ft). To provide the additional horsepower they had to enlarge the turbochargers by 30 percent, install a new custom exhaust manifold with downpipe and sport catalyst. In addition, an optimized intercooler and updated fuel and ignition systems are also part of the package. GAD also mentions a higher top speed without mentioning a figure, but at least we know that it’s more than the 186 mph (299 km/h) achieved by the AMG Performance Package-fitted model.