Whiteline Rear Sway Bar 27mm Adjustable – 2004-2007 Subaru STI

Whiteline Rear Sway Bar 27mm Adjustable – 2004-2007 Subaru STI

Maximum Rear Roll Stiffness for the GD STI
The Whiteline BSR37XXZ is the 27mm 3-point adjustable rear sway bar for the 2004-2007 Subaru STI — the maximum rear roll stiffness option in the Whiteline GD STI rear bar range. At 27mm, this bar is for dedicated track cars, time attack builds, and configurations where maximum rear roll control is required. Three adjustment positions allow fine-tuning within the maximum stiffness range.

DETAILS

• 27mm 3-point blade adjustable rear sway bar — maximum GD STI rear stiffness
• Solid spring steel, silver powder coat
• Includes mount bushings and hardware
• 3 adjustment positions
• Fitment: 2004-2007 Subaru STI (GD chassis)
• Track and competition use

When 27mm Is Required
The 22mm BSR37Z is for street and mixed use. The 24mm BSR37XZ is for track-oriented builds. The 27mm BSR37XXZ is for dedicated competition — time attack, circuit racing, and high-grip autocross configurations where absolute maximum rear roll control is needed. Running 27mm without matched front stiffness produces serious oversteer.

System Calibration for Maximum Stiffness
The BSR37XXZ pairs with the BSF36XXZ (27mm) front bar for a fully maximum-stiffness configuration. Both bars at maximum stiffness, matched spring rates, correct endlink geometry, and proper alignment settings produce a GD STI that is extremely capable on smooth circuit surfaces.

Three Positions for Adjustment
All three positions are within the high-stiffness performance range. The position choices allow tuning for specific circuit characteristics and tyre compounds — slightly softer for rougher surfaces, stiffer for maximum-grip setups.

Why Choose Whiteline

Whiteline has been engineering suspension components from their facility in Australia since 1979. Every product in their catalog is developed with a clear goal: measurable improvement in handling, stability, and tyre contact. Whiteline’s polyurethane bushings, sway bars, control arms, and alignment correction kits are engineered using finite element analysis and validated on track before they reach the market. Their components are direct-fit, bolt-on solutions designed for enthusiasts who want real performance gains without fabrication or custom work.

The RallySport Take

The absolute maximum rear stiffness option for the GD STI. This is competition hardware — use it in competition applications. Installation is a straightforward bar swap — remove the OEM bar, install the Whiteline unit with the provided polyurethane mount bushings, connect the endlinks. Start in the middle adjustment position and move from there. Adjustable endlinks are a worthwhile companion purchase if the car has been lowered, ensuring the bar operates at zero preload at the new ride height.

What’s in the Box

• 27mm 3-point blade adjustable rear sway bar — maximum GD STI rear stiffness
• Solid spring steel, silver powder coat
• Includes mount bushings and hardware
• 3 adjustment positions
• Track and competition use

Fitment