05-07 Subaru STI

The Flatout Suspension GR40-PRO is an extreme-duty off-road coilover suspension system built for drivers who demand maximum performance beyond the pavement. Designed for hardcore off-roaders, overlanders, and expedition builds, the GR40-PRO delivers the strength, adjustability, and endurance needed to handle the harshest terrain with confidence.

Unlike basic spacer lifts or traditional shock and spring combinations, the GR40-PRO features professional-grade inverted shocks, external reservoirs, and advanced bypass valving for superior control over rocks, washboard roads, sand, mud, and technical trails. With 0–3” of adjustable lift and full damping adjustability, this system is built for serious off-road performance.

Key Features

• 0–3” Adjustable Lift
  Increase ground clearance for larger tires and more demanding terrain.
• Inverted Shock Design
  Rally-proven construction provides exceptional strength and durability under extreme off-road abuse.
• External Reservoir Shocks
  Increased oil capacity improves cooling and reduces fade during long trail runs and harsh conditions.
• Advanced Bypass Piston Valving
  Smooths washboard roads, absorbs large impacts, and maintains control on technical terrain.
• Fully Adjustable Damping
  Fine-tune:
  • Rebound
  • High-Speed Compression
  • Low-Speed Compression
    Ideal for crawling, overlanding, towing, or high-speed desert driving.
• Fully Rebuildable Construction
  Designed for long-term serviceability and serious off-road use.
• Electroplated Shock Bodies
  Provides 7–10 years of corrosion resistance in mud, snow, rain, and salted environments.

Designed For

• Hardcore off-road enthusiasts
• Overland and expedition vehicles
• Heavy builds with rooftop tents, bumpers, winches, and cargo
• Drivers demanding premium off-road suspension performance

Customer Benefits

• Increased clearance and durability for extreme terrain
• Fade-resistant performance with external reservoirs
• Excellent stability under heavy loads
• Adjustable for crawling, fast trail driving, or loaded overlanding
• Built for long-term reliability in harsh off-road conditions