RENNtech ECU Upgrade | R231 | SL 550 | 500HP / 625LB-FT | 4.7L V8 BiTurbo | M278 mercedes-benz-ml-class--164---2006-2011--ml-320-cdi-esr8255656 ): 329 HP @ 5

):                               329 HP @ 5

GLK 350 (X204) Stock Performance:

Rated by RENNtech:               448 HP @ 5

GL550 (W166 | MY2013-15 | 4MATIC | M278 | 4

The rear spoiler offers a smooth transition of airflow over the trunk lid of the vehicle to ambient air and produces greater down force across the rear of the vehicle at speed

RENNtech ECU Upgrade | R231 | SL 550 | 500HP / 625LB-FT | 4.7L V8 BiTurbo | M278 mercedes-benz-ml-class--164---2006-2011--ml-320-cdi-esr8255656 ): 329 HP @ 5ECU Upgrade 500HP 625LB FT Gains: +52HP +87LB FT Our intermediate level ECU upgrade for the Mercedes M278 engine still offers huge gains in performance across the entire RPM range, but with a slightly reduced peak HP and torque from our standard tune. This is ideal for customers who want increased performance in their daily driver without worry of extra strain on driveline components or for areas and countries with extreme altitudes, temperatures or