RENNtech ECU Hand Held Tuner (HHT) for SLK 55 | R171 | 380 HP / 395 TQ | MY2005-2009 mercedes-benz-cla-class--118---2020-present--cla-35--amg-esr2775909 CLASS S LONG (W 221)

CLASS S LONG (W 221) 500 [ONLY USA] [2 Filters Required] (HP: 387 | Year: 05 >)

the factory settings do NOT allow the valves to fully open unless certain speed and/or RPM have been reached

536 HP @ 6

CLASS S LONG (V 220) 280 [2 Filters Required] (HP: 204 | Year: 98 > 05)

Jaguar F Type SVR (X152) 2018+

RENNtech ECU Hand Held Tuner (HHT) for SLK 55 | R171 | 380 HP / 395 TQ | MY2005-2009 mercedes-benz-cla-class--118---2020-present--cla-35--amg-esr2775909 CLASS S LONG (W 221)RENNtech ECU HHT (HandHeldTuner) for the R171 SLK 55 AMG. Up to 380HP and 395 LB FT TQ. Gains: +18HP & +17TQ. 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.