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M274 Downpipe, C300 RWD
Purchase M274 Downpipe, C300 RWD
  • SKU: 01-274-01625-8

    M274 Downpipe, C300 RWD

  • Advertised gains are estimates of HP and Torque “at the engine” calculated from gains as measured on a Dynojet Dynamometer in ideal conditions and typically show the largest possible change.  Actual gains are dependent on the following: Learn More about Crank HP Vs Wheel HP

    Model – Manufacturers use the same engine in multiple model vehicles and often times they are in a different state of tune, for example: 2008 C63 and a 2008 CLK Black Series.  Both have the same engine, but the C63 has 451hp while the CLK63 has 500hp.  Naturally the C63 will show more gains as it starts at a lower level.

    Model Year – Similar to above, as time progresses, Manufacturers tend to slightly increase power output via software from one year to the next or offer “Performance Packages” with increased power.  The engines remain largely unaltered and as a result, final tuned output remains the same, while the gains are lower as the starting point is now higher.

    Fuel – Fuel quality is HIGHLY important with performance vehicles.  Low quality and/or low octane fuel will greatly impact engine output and potentially even engine health.  Top tier brand premium fuels should always be used to achieve the best results possible.

    Drivetrain – All wheel drive has higher drivetrain losses than rear wheel drive.  This results in lower numbers when testing on a chassis dyno.  Wheel/tire size and weight will also impact chassis dyno results

    Weather/Conditions – Temperature, humidity, altitude, and air density all impact engine performance.  Heat, high humidity, and thin air will all work towards reducing engine output

    Engine Health – Higher miles tends to result in increased build up and lower compression which can and will impact engine output.  Properly maintained engines will have better performance than abused or neglected engines.

    Supporting modifications – The highest power levels require supporting modifications.  Depending on the engine, this could mean forged internals, built transmission, upgraded fuel system, 110+ octane race fuel, etc.

  • $439.00 $439.00

  • Prop 65 warning

    This product can expose you to chemicals including carbon black, silica - crystalline, formaldehyde, and lead which are known to the State of California to cause cancer, and lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to

Weistec Horsepower 270
Weistec Torque 318
Manufacturer Weistec
Street legal in all the US States No
Engine Family M274
Stock Horsepower 255
See more
year make model trim engine
2018 Mercedes-Benz C300 Base (W205) Turbocharged 2L I4 (M274)
2017 Mercedes-Benz C300 Base (W205) Turbocharged 2L I4 (M274)
2016 Mercedes-Benz C300 Base (W205) Turbocharged 2L I4 (M274)
2015 Mercedes-Benz C300 Base (W205) Turbocharged 2L I4 (M274)

Product Description

[ Expect delivery times of 8 weeks ] [ Needs ECU Tuning to run properly ]

Weistec Engineering offers the M274 Downpipe for the W205 C300 RWD models.  The downpipe was designed with the most sophisticated Computer Aided Design tools to ensure excellent fitment. The downpipe features 3 inch diameter piping and a laser cut precision flange to mate with factory mounting points, giving this system a perfect fit. Our M274 Downpipe features a CNC Machined 304 stainless steel turbine flange to mate with the turbo perfectly using the OEM clamp.  The M274 Downpipe connects to the rest of the exhaust using an OEM style adapter for a simple bolt in installation

This product will NOT fit the AWD C300

  *Product may not be emissions compliant. Check local laws prior to installation. 

Key Features:

  • 100% mandrel bent and TIG welded

  • Constructed of low carbon 304 Stainless Steel

  • CNC machined 304SS turbine flange

  • Laser cut mounting bracket

  • Fully brushed finish

  • Bolt-on installation

  • 1 hour instal time

  • Improved exhaust note

  • Improved exhaust flow

  • Improved turbo response