HKS Hipermax S Full Coilover Kit – Subaru Impreza WRX STI GDB (A-D) | Street & Track Damper System

The HKS Hipermax S Full Coilover Kit for the Subaru Impreza WRX STI GDB (chassis codes A through D) is a complete 4-corner coilover suspension system engineered by HKS — one of Japan's most respected performance suspension and engine management brands — for the GDB STI platform. The Hipermax S is HKS's street and track-oriented coilover system — delivering the ride height adjustability, damper tuning capability, and spring rate selection that the GDB STI's performance potential demands, in a complete kit that replaces the factory suspension at all four corners. The Hipermax S is engineered for GDB STI owners who want a significant suspension upgrade over the factory setup — improved handling precision, reduced body roll, and the ability to set the car's ride height and damper characteristics to match their specific driving application, whether street, track day, or time attack.

Key Features:

• Complete 4-corner coilover kit — full front and rear coilover assemblies replacing the factory suspension at all four corners — everything required for a complete suspension upgrade in a single purchase
• HKS Hipermax S damper technology — HKS's street and track-oriented damper specification — engineered for the GDB STI's suspension geometry, spring rates, and performance requirements
• Ride height adjustability — adjustable ride height via threaded spring perch — set the GDB STI's ride height to match your specific application and aesthetic requirements
• Damper adjustment — adjustable damper settings for tuning the suspension's response characteristics to match your driving style and application — softer for street comfort, firmer for track precision
• GDB (A-D) specific — engineered for the Subaru Impreza WRX STI GDB chassis codes A through D — verify your specific GDB chassis code before ordering
• HKS engineering quality — manufactured by HKS, one of Japan's most respected performance brands with decades of suspension development experience on the Subaru STI platform
• Complete kit — includes all four coilover assemblies and required hardware for installation

Performance Benefits:

• Ride Height Adjustment: The Hipermax S's threaded spring perch allows precise ride height adjustment at each corner — enabling the GDB STI to be set at the correct ride height for track use (lower centre of gravity, reduced aerodynamic lift) or street use (adequate clearance for road conditions and speed bumps). The ability to set ride height independently at each corner also allows corner weight adjustment for track applications where balanced corner weights are a priority.
• Damper Tuning: The Hipermax S's adjustable damper settings allow the suspension's response characteristics to be tuned to match the driver's preferences and the application's requirements — from a softer, more compliant setting for street driving comfort to a firmer, more responsive setting for track use where body motion control and transient response are priorities. The ability to adjust damping without changing springs allows the suspension to be optimized for different driving conditions without a full spring change.
• Improved Handling Precision: The Hipermax S's coilover design — with matched spring rates and damper valving engineered for the GDB STI's suspension geometry — delivers significantly improved handling precision over the factory suspension. Reduced body roll, improved transient response, and more consistent suspension geometry under load contribute to a more precise, more confidence-inspiring handling character that allows the GDB STI's AWD performance potential to be more fully exploited.
• Reduced Body Roll: The Hipermax S's spring rates are selected to reduce body roll compared to the factory suspension — keeping the GDB STI flatter through corners and improving weight transfer consistency. Reduced body roll improves the driver's ability to feel and manage the car's balance at the limit — a critical factor in both track performance and spirited street driving.

Specifications:

• Brand: HKS
• Part Number: HKS80300-AF002
• Barcode: 80300-AF002
• Series: Hipermax S
• Kit Type: Full coilover kit (4-corner)
• Application: Subaru Impreza WRX STI — GDB chassis — codes A through D
• Weight: 68.3 lbs (shipping weight)

Fitment Information:

• Subaru Impreza WRX STI — GDB chassis — codes A through D
• GDB chassis code reference:
  • GDB-A: 2001–2002 WRX STI (JDM)
  • GDB-B: 2002–2003 WRX STI (JDM)
  • GDB-C: 2003–2004 WRX STI (JDM / USDM)
  • GDB-D: 2004–2005 WRX STI (JDM / USDM)
• Note: Verify your specific GDB chassis code before ordering — the Hipermax S GDB (A-D) kit is not compatible with later GDB chassis codes (E onward) or the GRB/GVB chassis. A four-wheel alignment is required after coilover installation. Professional installation by an experienced Subaru suspension specialist strongly recommended.

What's Included:

• HKS Hipermax S front coilover assemblies (pair)
• HKS Hipermax S rear coilover assemblies (pair)
• All required mounting hardware
• Refer to HKS product documentation for complete kit contents and spring rate specifications

Installation Notes:

• Professional installation by an experienced Subaru suspension specialist strongly recommended — coilover installation requires correct torque specifications, correct spring perch height setting, and a four-wheel alignment after installation
• A four-wheel alignment is required after coilover installation — do not drive the vehicle at speed before a full alignment is performed
• Set ride height with the vehicle at kerb weight (fuel, fluids, and driver weight) for accurate ride height measurement — setting ride height on an unloaded vehicle will result in incorrect ride height under normal driving conditions
• Set damper adjustment to the manufacturer's recommended baseline setting before the first drive — adjust from the baseline after evaluating the suspension's behaviour on your specific roads and track
• Inspect all suspension components (control arms, bushings, ball joints, tie rod ends) before installation — worn suspension components will compromise the coilover system's performance and should be replaced before or alongside the coilover installation

Why HKS?

HKS is one of Japan's most respected and longest-established performance brands — with a product lineup spanning coilovers, exhaust systems, air intakes, turbochargers, ECU tuning systems, and engine components for a wide range of Japanese performance platforms. HKS's Hipermax coilover lineup is one of their most proven product lines — developed with decades of suspension engineering experience on Japanese performance platforms including the Subaru STI, Mitsubishi Evo, Nissan GT-R, and Toyota GR86. For GDB STI owners who want a coilover system from a brand that genuinely understands the platform's suspension requirements and performance potential, HKS Hipermax S is a well-regarded choice.

Perfect For:

• Subaru Impreza WRX STI GDB (A-D) owners seeking a significant suspension upgrade over the factory setup — improved ride height adjustability, damper tuning, and handling precision for street and track use
• GDB STI track day and time attack builds where the factory suspension's ride height, spring rates, and damper characteristics are limiting factors in handling performance
• Street performance GDB STI builds where a quality coilover system delivers improved handling precision and a lower, more aggressive stance without sacrificing daily drivability
• Owners who want a complete 4-corner HKS coilover kit from a brand with proven Subaru STI suspension development experience

Note: Verify GDB chassis code (A-D) before ordering — not compatible with GDB-E onward or GRB/GVB chassis. Four-wheel alignment required after installation. Professional installation strongly recommended. Set ride height at kerb weight for accurate measurement.