DISCLAIMER: This is a made to order item. The lead time for this product is 4-8 weeks.

Flatout GR40-PRO Coilovers for 2015–2021 Subaru STI

The Flatout GR40-PRO Suspension System is a professional rally- and motorsport-ready coilover kit designed for the 2015–2021 Subaru STI. Built for rally, rallycross, and high-performance motorsport, the GR40-PRO provides unmatched durability, adjustability, and precision handling for drivers who demand the ultimate performance on and off the track.

Featuring inverted shocks with external reservoirs, 3-way damping adjustability, and high-performance linear springs, the GR40-PRO is engineered to optimize your STI’s suspension for aggressive driving, technical stages, and full-load stability.

Key Specifications

• Motorsport-Grade Design → Built for rally and competition use.

• 2 Inverted Front Assemblies with Reservoirs → 7” front travel, radial bearings, and linear rate springs.

• 2 Inverted Rear Assemblies with Reservoirs → 6” rear travel, secondary helper spring, and linear rate springs.

• 40mm Insert → High-strength internal component for durability.

• External Reservoirs → Increased oil volume prevents fade under extreme conditions.

• 3-Way Damping Adjustment → Rebound, low-speed, and high-speed compression adjustable.

• Rebuildable Inverted Shocks → Long-term serviceability and performance tuning.

• Premium Components → CNC-machined aluminum pistons, stainless steel shims, electro-plated nickel cartridges.

• Spherical Bearing Upper Mounts → Precision alignment and reduced NVH.

• Brackets for Sensor Lines → Retains OEM sensor placement.

• Individual Parts Available → Easily replace or upgrade components.

Why Choose GR40-PRO for Your STI?

• Rally-proven coilovers designed for professional drivers and serious enthusiasts.

• Handles extreme track and off-road conditions with precision and confidence.

• Fully adjustable to match driving style, load, and terrain.

• Durable and serviceable for long-term competitive use.

The Flatout GR40-PRO Coilovers give your 2015–2021 Subaru STI the professional rally-grade suspension it needs — combining strength, adjustability, and precision for peak motorsport performance.