RENNtech Intermediate ECU Upgrade | R231 | SL 63 AMG | 638 HP / 695 LB-FT | M157 | 5.5L V8 BiTurbo | MY2012-14 mercedes-benz-s-class--221---2007-2013--s-63-amg-esr7422703 443awhp @ 5

443awhp @ 5

Intermediate ECU Upgrade | Up to 638HP / 695LB-FT | Gains: +33HP & +49LB-FT

No modifications to the OEM part or fender needed

Note: Mercedes M137 engine performance when measured obtains higher numbers that rated from factory

Its unique design complements the refined trunk lines yet offers a more aggressive

RENNtech Intermediate ECU Upgrade | R231 | SL 63 AMG | 638 HP / 695 LB-FT | M157 | 5.5L V8 BiTurbo | MY2012-14 mercedes-benz-s-class--221---2007-2013--s-63-amg-esr7422703 443awhp @ 5Intermediate ECU Upgrade Up to 638HP 695TQ Gains: +75HP +101TQ RENNtech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal! Our proprietary tuning module stores both the RENNtech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose directly to the ECU. Programming takes only a few minutes and the vehicle