Tein 2015 Subaru WRX STi Street Basis Z Coilovers

Refined Ride Height Control for Subaru WRX, Subaru WRX STI

The Tein Street Basis Z coilover kit (GSSB0-8USS2) brings adjustable ride height and a twin-tube damper design to your Subaru WRX, Subaru WRX STI. Built around Tein's sealed twin-tube damper system, GSSB0-8USS2 delivers a longer stroke and smaller repulsive force than a strut-style damper, so ride comfort stays smooth at low speed while the chassis stays stable and composed at highway speed. Every GSSB0-8USS2 kit ships with Tein's No-Sag Spring, cold-formed from SAE9254 steel for long-term sag resistance, and uses the vehicle's factory upper mounts so installation stays straightforward. Drivers who want a lower stance and sharper handling without giving up daily-driver comfort consistently choose GSSB0-8USS2 for that balance.

Key Features

• Twin-tube damper system on GSSB0-8USS2 for a longer stroke and smoother low-speed ride quality
• Ride height adjustable via the lower spring seat for a custom stance
• No-Sag Spring cold-formed from SAE9254 steel with a minimum tensile strength of 200 kgf/mm2
• Sealed shell construction (narrowed top, oil/gas injected, crimped seal) for cost-efficient durability
• TEIN-Green 2-layer 1-bake powder coating (Japanese patent 4347712) resists peeling and flaking
• ZTP-coated ride-height adjustment thread resists abrasion and rust-seizure
• High-performance damper oil formulated for stable viscosity, anti-foaming, and heat resistance
• Uses the vehicle's OE upper mounts (not included), keeping installation cost down

Fitment Table

Specifications

What's Included

• 1x set of GSSB0-8USS2 Street Basis Z coilover dampers (front and rear)
• No-Sag springs pre-installed on each damper
• Lower spring seats for ride height adjustment
• Mounting hardware required for installation to the damper body

About Tein

Tein has spent decades engineering coilover suspension for street and motorsport applications, and the Street Basis Z line represents the brand's entry point into true full-length adjustable coilovers. Each kit is built with the same damper philosophy Tein uses across its performance range, tuned specifically for street comfort and everyday drivability rather than outright track performance. Tein's manufacturer-backed build quality and attention to corrosion resistance are why the brand remains a trusted name among enthusiasts upgrading their suspension.

FAQ

The GSSB0-8USS2 is a Tein Street Basis Z coilover kit designed for Subaru WRX, Subaru WRX STI. It provides adjustable ride height with a fixed damping rate, using a twin-tube damper design for a comfortable street ride.

No, Street Basis Z uses a fixed, non-adjustable damping rate. Drivers who want adjustable damping should look at the Street Advance Z line instead.

No, this kit reuses the vehicle's factory upper mounts, which are not included in the box.

Ride height is adjusted via the lower spring seat, which threads up or down the damper body to raise or lower the vehicle independently of spring preload.

Street Basis Z is EDFC-compatible on many applicable vehicles, though compatibility should be confirmed for your specific chassis before purchasing an EDFC controller.

Street Basis Z is tuned for spirited street driving and daily commuting, prioritizing ride comfort alongside a lowered stance rather than dedicated track performance.

Since this is a bolt-in suspension modification, local inspection requirements vary. Check your regional regulations before installation.

Installation is possible in a home garage with the right tools, but the job goes considerably faster with a lift, spring compressor, and a second set of hands.

Install Instructions

1. Raise and safely support the vehicle, then remove the wheels.
2. Disconnect the factory shock/strut assembly, including any brake line brackets or sway bar end links.
3. Remove the factory strut/shock assembly and transfer or retain the OE upper mount for use with GSSB0-8USS2.
4. Install the GSSB0-8USS2 damper assembly into the vehicle, torquing all mounting hardware to factory specification.
5. Set the lower spring seat to the desired ride height on all four corners evenly.
6. Reinstall the wheels, lower the vehicle, and torque lug nuts to spec.
7. Get an alignment performed before driving the vehicle on public roads.