RENNtech Stage II Turbo Upgrade Package | X290 | GT 63 (S) AMG | 1,017 HP / 871 LB-FT | 4.0L V8 BiTurbo | M177 | MY2019+Includes Upgraded Turbos, ECU Upgrade, upgraded CPC Unit and Fuel System Upgrade. Gains: Up to +336HP +137LB FT The Mercedes X290 GT 63 (S) AMG 4 Door Coupe comes with the newest engine fully developed by AMG, the companys Affalterbach based performance division and long fabled engine builder. The result is nothing short of spectacular and the 4. 0L V8 BiTurbo engine is an incredible platform to build performance upon. In addition to that, the all new