XYZ Racing Hollow Rear Brake Kit — Subaru IMPREZA GRB 2.5L (STI) φ 315/ φ 191 (2007-2013)

The GRB STI sends roughly a tonne and a half of all-wheel-drive turbo hatch through its rear axle on every corner entry, and the factory rears are the first thing to fade once a track session stretches past a handful of hard laps. The XYZ Racing Hollow Rear Big Brake Kit for the Subaru Impreza GRB 2.5L (STI) targets exactly that weakness with a 315mm two-piece floating rotor that sheds heat and rotating mass without changing the back of the car’s behaviour you already trust on a fast road.

Built for the 2007-2013 GRB chassis, this rear kit pairs a high-temperature disc with a caliper and pad package you spec to the way you actually drive, Street, Sport or full Racing compound. It is the rear-axle half of a properly balanced upgrade, supplied as a matched pair of left and right corners, not a styling add-on.

What this brake kit does for your 2007-2013 Subaru Impreza GRB 2.5L (STI)

On a heavy symmetrical-AWD car, rear brake stability is what keeps the back planted as you trail off the pedal into a corner. The 315mm two-piece floating rotor runs cooler than the original, so repeated stops from speed hold a firmer, more predictable pedal rather than going long and soft. The floating construction lets the friction ring expand and shed heat independently of the bell, trimming rotating and unsprung mass at each rear wheel, which sharpens turn-in and lets the dampers work over kerbs and broken tarmac. Choose the Racing compound for circuit heat, the Sport compound for hard road use with the occasional track day, or the Street compound for a quieter, low-dust daily setup: the bite changes, the fitment does not.

About the Hollow Rear Big Brake Kit

This is a direct-fit rear big brake kit for the GRB STI rather than a universal bracket-and-disc bodge. The 315/191 rotor dimensions match the car’s factory rear-axle geometry, so the disc, caliper and pads bolt up to the existing hub and brake lines, with braided lines available to firm up pedal feel further. The two-piece floating disc exists to manage heat: letting the friction ring expand against the alloy bell drops thermal distortion while keeping rotating inertia low, which is why it resists fade across a session instead of after a single stop. Three pad compounds cover the spread from road manners to track abuse. The caliper is a hollow-cast forging as standard, painted Red, Yellow, Gold, Black or Anodized Black at no cost, with a Custom Color in any Pantone for £150 and premium polished-forged and candy finishes on offer, plus an optional Hollow Racing upgrade rated to 1000C for dedicated track work. Disc faces come drilled or slotted at the same price, and the centre bell upgrades to a five-colour anodized two-tone or titanium at checkout. The result is a rear end that recovers its bite lap after corner, not one that needs a cool-down lap to feel normal again.

Fitment for the Subaru Impreza GRB 2.5L STI (2007-2013)

This kit is built for the Subaru Impreza GRB 2.5L (STI) hatchback, 2007 to 2013, in the rear position. It uses the 315/191 rear rotor dimensions specific to that chassis: confirm your car is the GRB STI variant before ordering, as the non-STI Imprezas of the same era run different rear hardware.

What buyers also search for

• Subaru Impreza GRB STI rear big brake kit for track days and fast road use
• 315mm two-piece floating rear rotor upgrade for the 2007-2013 Impreza STI
• GRB STI rear brake fade fix with Racing, Sport or Street pad compounds
• Subaru Impreza STI rear caliper colour options including Red, Black, Gold and a Custom Pantone
• Direct-fit GRB rear brake kit that keeps factory line and hub geometry

Match the rear to your front setup, pick your pad compound and caliper colour from the options above, and configure yours.