The German tuner GAD Motors revealed a performance program for the Mercedes-Benz CLS 63 AMG.
The most powerful CLS 63 AMG offered by the Stuttgart carmaker is fitted with the AMG Performance Package and delivers 558 HP and 799 Nm. GAD Motors says that isn’t enough and increase the engine output to 803 HP (590 kW) and 1.149 Nm (847 lb-ft).
The German tuner enlarge the turbochargers by 30%, install a new exhaust manifold and they optimized the intercooler. The ignition system was also modified to provide the impressive output. 
GAD Motors told us that their creation has a higher top speed without mentioning a figure.  

Source: GAD Motors