M256 // 3.0T // 43, 450, 53, 500 // Tuning Software
Feel your vehicle unleash more power, accelerate with confidence, and enjoy a more thrilling drive.
Our tuning software optimizes the engine and transmission control unit to deliver increased torque and responsiveness — all without compromising reliability or safety.
No add-on boxes — just a fully integrated software solution tailored perfectly to your vehicle.
Benefit from a calibration refined through countless miles of testing on both the dyno and the road. Installation is done directly in the control unit — no hardware modifications or invasive changes to your vehicle required. And if you want, you can always revert back to the original factory software.
Enjoy a balanced blend of noticeable power gains and improved fuel efficiency — especially for city and everyday driving. The software works reliably with your vehicle’s stock hardware and supports mild upgrades such as enhanced intake, sport exhaust, or a more efficient intercooler.
✔ Developed by skilled calibration experts and engineers
✔ No hardware changes or tuning boxes needed
✔ Boosts power and torque while keeping everyday drivability
✔ Engineered with precision on both dyno and road testing
✔ Compatible with stock hardware and mild performance upgrades
✔ Fully reversible to your vehicle’s original factory software
| M256 | Stock | Stage 1 |
|---|---|---|
| Power | 367 - 435 hp | 424 - 465 hp |
| Torque | 500 - 520 Nm | 600 - 630 Nm |
| Recommended Fuel | 98 RON 93 AKI |
102 RON 97 AKI |
| Make | Model | Year |
|---|---|---|
| AMG | GT 43 (X290) | 2018 - now |
| Mercedes | CLS 450 (C257) | 2018 - now |
| Mercedes | E 450 (213/238) | 2018 - now |
| Mercedes | GLE 450 (V167) | 2018 - now |
| Mercedes | GLS 450 (X167) | 2019 - now |
| Mercedes | S 450 (223) | 2020 - now |
| AMG | GT 53 (X290) | 2018 - now |
| Mercedes/AMG | CLS 53 (C257) | 2018 - now |
| Mercedes/AMG | E 53 (213/238) | 2018 - now |
| Mercedes/AMG | GLE 53 (167) | 2019 - now |
| Mercedes | S 500 (223) | 2020 - now |
Provider:
KM Engineers GmbH
Albert-Einstein-Str. 2 b
77656 Offenburg
Germany
Contact:
Email: info@km-tuning.com
Phone: +49 781 12559870
Important Information Regarding Road Use
- The use of this software is strictly prohibited on public roads. It is intended exclusively for research, development, motorsport, or testing purposes on private property.
- The user is solely responsible for ensuring compliance with all applicable laws and regulatory requirements.
Disclaimer of Liability
Use of this software and hardware is at your own risk. Any modifications to vehicle control units may result in unexpected behavior, malfunctions, or damage to the vehicle. The provider accepts no liability for direct or indirect damages, consequential damages, vehicle breakdowns, or legal infringements arising from the use of this software or hardware.
The user is fully responsible for ensuring legal compliance and the operational safety of the vehicle. In particular, the provider disclaims any responsibility for use on public roads or for any resulting consequences.
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The performance figures are provided for guidance purposes only. Actual performance may vary due to factors such as the vehicle's age, maintenance condition, and manufacturer tolerances.
The vehicle list may not be comprehensive and is provided for reference only. No guarantee of completeness is implied.
Not sure if your vehicle is compatible? Feel free to contact us via our contact form or our service hotline. Our team will be happy to assist you.
Important Information for Mercedes and AMG Models from 2020 Onwards:
Vehicles equipped with MD1/MRD1 or MG1/MRG1 ECUs feature a highly protected engine control unit that must be unlocked before any ECU tuning can be performed. When purchasing this Stage 1 tuning, the ECU unlock is already included at no extra cost.
Please note: The unlock and tuning process can only be carried out on-site at our facility. The entire procedure takes approximately 2 to 4 hours, allowing you to drive your vehicle home the same day.
Advanced Performance Levels
If you’re looking for even more power or have specific performance needs, we offer Stage 2, Stage 3 and fully customized tuning solutions upon request. This allows you to tailor your vehicle exactly to your preferences and driving style — whether that means significantly higher performance, specialized modifications, or bespoke calibrations. Feel free to contact us for a personalized consultation.
Customers worldwide appreciate our years of experience, precision work, and personalized service. Whether you need tailored advice, custom solutions, or flexible scheduling, we’re here to elevate your vehicle’s performance. Contact us via our service hotline or contact form.