GrimmSpeed 4-Piston Brake Caliper Kit (326mm Rotor) - Red - 2002-2021 Subaru WRX / STI

Engineered for Performance

The stock single-piston calipers found on most Subaru models are functional but not designed for the demands of aggressive driving, track use, or extensive performance builds that many Subaru enthusiasts pursue. GrimmSpeed’s 4-Piston Brake Caliper Kit fills this gap by offering a purpose-built, fixed caliper system specifically tailored for Subaru vehicles. This setup provides balanced stopping power, improved heat dissipation, and a consistent pedal feel, enhancing braking performance and driver confidence. Designed and tested under real-world conditions, this kit delivers a true performance upgrade without the hassle of sourcing used Brembos or fitting custom brackets.

Complete, Application-Specific Upgrade

Each GrimmSpeed kit is built to perfectly fit specific Subaru models, combining forged aluminum calipers with the correct rotor and bracket configuration for your setup. Offered in either Red or Gunmetal Gray anodized finishes, the calipers are made to resist heat and corrosion while presenting a sleek, motorsport-ready look. Suitable for a wide range of uses—from daily-driven street cars to dedicated track machines—this kit provides the reliable stopping power and confidence Subaru drivers expect.

 

DETAILS:

• Forged 6061-T6 Aluminum Caliper Body – 2-piece design, hard anodized for strength and corrosion resistance

• Dual Piston Setup – 44mm primary and 41mm secondary pistons provide even pad pressure and reduced taper

• Heat-Managed Pistons – Type 3 hard anodized and vented for superior thermal performance

• Lightweight Design – Approximately 9.9 lbs per corner with bracket and hardware

• Pad Compatibility – FMSI D1001 or D968 (varies by application)

• Rotor Compatibility – Works with commonly available Subaru OEM and STI rotors

• No Brake Lines Required – Compatible with factory lines (new lines may be recommended depending on vehicle)

What’s Included

• (2) GrimmSpeed 4-Piston Brake Calipers (choose Red or Gunmetal)

• (2) Vehicle-Specific Billet 4140 Steel Caliper Brackets

• Full Hardware Kit:

  • Bridge bolts

  • Banjo bolts

  • Crush washers

  • Bleeder dust caps

  • Caliper guide pins

  • Security cotter pins

  • Caliper spring bridges + bolts

• Printable 1:1 Fitment Template

• Install Instructions

Fitment

• 02-21 WRX
• 04-21 STI
  • Rotor Size: 326mm x 30mm - STI fitment rotor
  • Pad Type: "F50" or FMSI D1001 - OEM 4-Piston STI Brembo Pads
  • Designed for use with OEM-style hubs and rotors — no knuckle swaps or custom adapters required

         *OEM x-ref - 5x100 - 326mm x 30mm Rotor - 2004 STI - Also came on some BRZ (5x100 Cars Only) Part No.-26300FE001

         *OEM x-ref 5x114.3 - 326mm x 30mm Rotor - Fit 4 pot Brembos (5x114.3 Cars Only) 2005-2017 WRX/STI   Part No.-26300FE070