HKS 80330-AF009P Hipermax S Series Coilover Suspension Full Kit

The HKS Hipermax S Series Coilover Kit (80330-AF009P) is a full coilover suspension system engineered for the Subaru WRX STI (VAB/EJ20 Turbo) and WRX S4 (VAG/FA20 Turbo). Born from nine years of development since the MAXIV GT platform, the Hipermax S represents HKS's most advanced street-focused coilover line, delivering a new standard of Driving Comfort — balancing ride quality, handling precision, and long-term durability.

Key Features:

• Single-Tube Monotube Design: Separates the gas and oil chambers to allow a larger diameter piston, producing consistent, high-quality damping force across all driving conditions.
• Dual Preload Valve System (Dual PVS): Evolved from the proven PVS introduced in the MAX IV GT, the Dual PVS suppresses unnecessary damping force at higher piston speeds — significantly improving ride comfort without sacrificing handling performance.
• 30-Step Damping Force Adjustment: Wide-range needle jet with an improved shape expands the oil relief channel, making each of the 30 adjustment steps more distinct and usable for a broader range of driving stages.
• Advanced Bump Stop Rubber: Redesigned bump stop rubber reduces body roll while delivering ride comfort that traditional hydro bump stop designs cannot match.
• PNE Anti-Corrosion Coating: Provides 5x better durability compared to standard galvanizing — a technology derived from HKS's Snow Edition development program.
• Inverted Front Strut Design: Large lateral forces are distributed over a greater area, increasing rigidity under high loads or when running larger wheel packages, while reducing unsprung weight for sharper handling response.
• Strengthened Rubber Upper Mounts: Absorb small road vibrations while providing a firmer connection than stock mounts, improving steering feedback and overall feel.
• Full Kit — Pre-Assembled: Includes front and rear coilover assemblies, spanner wrenches, and a damper adjustment tool.
• 3-Year Warranty: Backed by a 3-year warranty — triple the coverage of the previous MAX IV GT series — reflecting HKS's confidence in the optimized internal components and build quality.

Specifications:

• Spring Rate — Front: 88 N/mm (9 kgf/mm) | Rear: 69 N/mm (7 kgf/mm)
• Free Length — Front: 220 mm (Barrel) | Rear: 170 mm (Barrel)
• Damping Force (Front @ 0.1 m/sec) — Stretch: 809 N | Shrink: 505 N
• Damping Force (Rear @ 0.1 m/sec) — Retention: 363 N | Retraction: 348 N
• Vehicle Height Adjustment — Front: 0 to -31 mm (STI VAB) | Rear: 0 to -59 mm (STI VAB)
• Spring Rate Change Available at Factory: ±10 N/mm (±1 kgf/mm) Front and Rear

The HKS Hipermax S 80330-AF009P is the ideal upgrade for enthusiasts seeking a premium Japanese-engineered coilover that excels both on daily commutes and spirited driving, without the harshness of track-only suspension systems.