StopTech Stainless Steel Brake Line Kit — F30/F32/M3/M4

Built in the United States and fully DOT-compliant, StopTech engineered this kit as a true direct-replacement fitment. No cutting, no splicing, no fabricating custom lengths — the lines are designed to match OEM routing and connection points exactly. The stainless steel braid over the inner PTFE liner also means these lines won't crack, swell, or degrade the way rubber lines do after years of heat cycling and exposure to brake fluid, road grime, and temperature swings. For track day regulars especially, that durability is significant.

This single kit covers an extensive range of F-chassis applications, including the F30 3 Series (320i through 340i), F32 4 Series (428i through 440i), Gran Coupe variants, xDrive models, and critically, the F80 M3 and F82 M4 from 2015 onward. Model year coverage runs from 2012 through 2020, making this a go-to kit whether you're building out a track-focused M4 or upgrading a well-used 328i. StopTech part number 950.34032 — confirm your model year and drivetrain in the compatibility list before ordering.

If you're already running upgraded pads and rotors, stainless lines are the logical next step to complete a properly sorted brake system. And if you haven't touched the brakes at all, this is genuinely one of the highest-return mods on the list — under $100, bolt-on installation, and a difference you'll notice the first time you push the car.