2015-2021 Mercedes C300 ECU Tune GLC300 E300 – M274 2.0 Turbo

A custom ECU calibration for the Mercedes-Benz M274 2.0L turbocharged four-cylinder, written around your specific car, fuel and hardware rather than pulled off a shelf. Sharper throttle, stronger mid-range torque, and cleaner power delivery — with every factory safety system left intact.

Up to 320 hp / 340 lb-ft on a Stage 2 setup — calibration running with supporting bolt-ons (catless downpipe and high-flow intake filter). Tune-only output is lower and varies with fuel grade, ambient conditions and the hardware already on the car.

What the Tune Delivers

• Stronger mid-range torque — where the M274 actually lives in street driving
• Sharper throttle response — reduced pedal lag and quicker boost onset
• Refined boost and torque control — smoother delivery under load, not just a taller peak
• Better part-throttle drivability — improved cooperation with the transmission in normal driving
• Factory safeguards retained — knock control, thermal limits and torque protection all remain active

Vehicle Compatibility

RWD and 4MATIC both supported. If you are unsure which engine your car has, send us your VIN and we will confirm fitment before you order.

Build Your Package

Use the options above to add hardware alongside the calibration. Adding it at the same time means the file is written around the exact parts on your car from day one, instead of paying for a re-flash later.

• + Catless Downpipe — removes the main restriction directly after the turbo for quicker spool, stronger mid-range and a deeper tone. See the emissions notice at the top of this page.
• + K&N Performance Air Filter — washable, reusable high-flow drop-in for the factory airbox

What's Included

• Custom ECU calibration developed for your car, fuel grade and modification list
• OBD flashing cable and handheld programmer
• Return-to-stock file
• Direct support through the flash process

Off-road use only. Not legal for use on emissions-controlled vehicles or public roads.