RENNtech ECU+ Upgrade | W213 | E63 AMG (S) 4MATIC+ | 773 HP/778LB-FT | 4.0L V8 BiTurbo | M177 | MY2018-2023ECU+ Upgrade Up to 773 HP 778 LB FT Gains: +82 HP & +84 LB FT RENNtech tuning products are certified to meet CARB standards in all 50 States. 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