How many levels of damping adjustment does the Coilover Kit for GRB have?

Thirty. HKS uses its WR Needle mechanism, which widens the oil relief channel so each of the thirty clicks makes a clearer difference than the previous range managed. The reshaped needle also extends the soft end of the adjustment, which is what makes the kit usable on a street car rather than only on track.

Does this kit use pillow ball upper mounts?

No. HKS fits its strengthened rubber upper mount at the front of this kit, revised in cross section and material to tighten the mount over stock while still absorbing small body vibrations. There is no spherical bearing and no camber adjustment built into the mount, so alignment is set with the factory adjustment the car already has.

Is ride height adjustable without giving up suspension travel?

Yes. The damper bodies are length adjustable, so ride height is set by changing body length rather than by winding a spring seat down into the available stroke. That keeps suspension travel intact at a lowered ride height, which is the practical difference between a full coilover kit and a spring and seat arrangement.

Why does HKS warranty the HIPERMAX S for three years?

HKS moved the range from one year to three after reworking the internal structure and bringing manufacturing in house. Bench and road durability testing gave the correlation needed to extend the term. Three years is unusual on a sports coilover and is one reason the S range exists in its current form.

Can the Coilover Kit for GRB be revalved or rebuilt later?

Yes. HKS offers a spec change service that alters the damping specification of the Coilover Kit for GRB, and a full overhaul for kits that have covered serious mileage. Both run through HKS rather than a third party, which is worth knowing on a car that gets driven year round.

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Description

HKS HIPERMAX S Coilover Kit for GRB Subaru Impreza WRX STI

HKS’s Coilover Kit for GRB Subaru Impreza WRX STI puts the current S generation under the hatch and sedan STI. A single-tube damper keeps gas and oil in separate chambers, which allows a larger piston and a steadier damping force. The front is an inverted strut, so lateral load spreads across a wider area and the heavy part of the damper moves to the body side. Thirty levels of adjustment run through the WR Needle, whose reshaped relief channel makes each click count and pushes the soft end further than HKS managed before. HKS supplies the Coilover Kit for GRB as a complete four-corner set rather than a front or rear pair.

Design and Performance

Dual PVS is what changes how the car feels on a real road. The preload valve system cuts high-speed damping while keeping body movement in check, so the shaft extends more readily and the tire stays in contact over a broken surface, while fast compression still builds force quickly enough to absorb the hit. Working with it is the Advanced Bump Rubber, longer and softer than a conventional stop, which makes contact earlier in the stroke and loads gradually instead of arriving as a wall at the end of the travel. What HKS was chasing is a suspension that rides rather than crashes.

Construction

The damper bodies are length adjustable, so ride height changes without eating into the stroke. PNE coating replaces standard galvanising and HKS rates it at five times the corrosion durability, which matters on a car driven through winter. The front upper mount is the strengthened rubber design rather than a spherical bearing, revised in section and compound to firm up the mount over stock while still absorbing small vibrations. Aluminium brackets and a machined, chamfered top plate finish it, and HKS handles spec changes and overhauls when the kit needs revalving later.

Features

Single-tube damper with separated gas and oil chambers and a large-diameter piston
30 levels of damping adjustment through the WR Needle mechanism, with a usable soft end for street driving
Dual PVS preload valve system, cutting high-speed damping while holding body movement in check
Advanced Bump Rubber that loads progressively rather than ending the stroke abruptly
Inverted front strut, moving damper mass to the body side and spreading lateral load
PNE coating, rated at five times the corrosion durability of standard galvanising
Three-year HKS warranty, with spec change and overhaul service available

Applications

Subaru Impreza WRX STI: GRF hatchback | 2008-2014 | EJ257
Subaru Impreza WRX STI: GVF sedan | 2011-2014 | EJ257

Notes

The front upper mounts are the strengthened rubber type; this Coilover Kit for GRB does not include pillow ball mounts or mount-based camber adjustment
Supplied as a full kit for all four corners
California Prop 65 warning applies to this product
Spec changes and overhauls are carried out by HKS rather than a third party
Browse the full HKS range on Bulletproof Automotive

Frequently Asked Questions

How many levels of damping adjustment does the Coilover Kit for GRB have? Thirty. HKS uses its WR Needle mechanism, which widens the oil relief channel so each of the thirty clicks makes a clearer difference than the previous range managed. The reshaped needle also extends the soft end of the adjustment, which is what makes the kit usable on a street car rather than only on track.
Does this kit use pillow ball upper mounts? No. HKS fits its strengthened rubber upper mount at the front of this kit, revised in cross section and material to tighten the mount over stock while still absorbing small body vibrations. There is no spherical bearing and no camber adjustment built into the mount, so alignment is set with the factory adjustment the car already has.
Is ride height adjustable without giving up suspension travel? Yes. The damper bodies are length adjustable, so ride height is set by changing body length rather than by winding a spring seat down into the available stroke. That keeps suspension travel intact at a lowered ride height, which is the practical difference between a full coilover kit and a spring and seat arrangement.
Why does HKS warranty the HIPERMAX S for three years? HKS moved the range from one year to three after reworking the internal structure and bringing manufacturing in house. Bench and road durability testing gave the correlation needed to extend the term. Three years is unusual on a sports coilover and is one reason the S range exists in its current form.
Can the Coilover Kit for GRB be revalved or rebuilt later? Yes. HKS offers a spec change service that alters the damping specification of the Coilover Kit for GRB, and a full overhaul for kits that have covered serious mileage. Both run through HKS rather than a third party, which is worth knowing on a car that gets driven year round.

About HKS

HKS is a Japanese performance engineering brand founded in 1973 and headquartered in Fujinomiya, Shizuoka, with a long-standing reputation for developing high-quality aftermarket parts and motorsport-proven technology for enthusiast and professional applications. Known for innovations in turbocharging and engine performance, HKS produces a broad range of components including exhaust systems, turbo kits, electronics / engine management, and suspension solutions, with product development heavily influenced by decades of involvement in racing disciplines such as circuit time attack, drag, and drifting.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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HKS HIPERMAX S Coilover Kit for GRB Subaru Impreza WRX STI [80330-AF001]

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HKS HIPERMAX S Coilover Kit for GRB Subaru Impreza WRX STI

Design and Performance

Construction

Features

Applications

Notes

Frequently Asked Questions

About HKS

Reviews