Sequential Sound+ Tweeter Audio Booster Kit – GTS 86 / GR86 / BRZ - Japan Made

Custom made from Japanese-Made Audio Enhancement Upgrade Plug & Play

Transform the factory sound system in your Toyota 86, GR86, or Subaru BRZ with the Sequential Sound+ Tweeter Audio Booster Kit — a unique Japanese-made plug-and-play audio upgrade engineered to dramatically improve clarity, vocal presence, and overall listening experience without replacing speakers or requiring complicated audio modifications.

Developed and manufactured in Japan by the audio enthusiasts at ChikiParts, this custom-engineered solution combines specialist crossover tuning with OEM-style integration to unlock hidden sound quality from the factory audio system while maintaining complete reversibility and factory-like installation.

Designed specifically for 6-speaker vehicles, the system installs inline between the factory vehicle wiring and tweeter speakers using specially engineered crossover circuitry that restores audio frequencies commonly filtered out by the OEM system. The result is noticeably clearer vocals, improved staging, enhanced detail, and a richer overall sound profile for music, podcasts, and everyday driving.

No coding, tuning, or permanent modification required.

Key Features

• Designed for Toyota 86 / GR86 / Subaru BRZ (6-speaker systems)
  
• Japanese-made custom audio enhancement solution
• Developed in collaboration with ChikiParts Japan
  
• Plug-and-play installation with OEM-style connectors
  
• No coding or programming required
  
• Fully reversible installation
  
• Enhances clarity, vocals, and sound staging
  
• Restores frequencies filtered by factory audio wiring
  
• Professionally tuned crossover design
  
• No additional power source required
  
• Compatible with OEM and many aftermarket speaker setups
  
• Installs in approximately 10–20 minutes

How It Works

The Sequential Sound+ Booster Kit uses a specially engineered crossover integrated into the cable harness to restore audio frequencies typically filtered out by the factory wiring system.

By unlocking frequencies in the critical 3000Hz–7000Hz vocal range, the system produces:

• Cleaner and clearer vocals
  
• Improved audio separation and balance
  
• More detailed music playback
  
• Enhanced stereo imaging and sound stage

The difference is immediately noticeable without replacing your factory head unit or speakers.

Sound Characteristics

• Sharper vocal clarity
  
• More balanced and centered audio presentation
  
• Improved detail in music and podcasts
  
• Enhanced spatial sound perception inside the cabin

Plug & Play Installation

Simple OEM-style installation designed for enthusiasts of all experience levels.

• Remove factory tweeter grille using included trim tool
  
• Disconnect factory tweeter harness
  
• Connect Sequential Sound+ inline harness
  
• Reinstall grille and enjoy improved sound

No cutting
No coding
No permanent modifications

Compatibility

Compatible with factory 6-speaker audio systems only

Works with:

• Toyota 86
  
• Toyota GR86
  
• Subaru BRZ

Compatible with factory and many aftermarket speakers retaining OEM wiring

Additional vehicle-specific Sound+ solutions may also be available for selected Mazda platforms including Mazda 2, Mazda 3, and Mazda CX-5 models. Please contact us to confirm compatibility for your vehicle.

What’s Included

• 2 × Sequential Sound+ Booster Harnesses (Left & Right)
  
• Trim Removal Tool
  
• Installation Instructions

Important Notes

Compatible only with factory-supported speaker wiring layouts

Why Choose Sequential Racing?

Sequential Racing focuses on enthusiast-driven upgrades that deliver real-world improvements without unnecessary complexity. The Sequential Sound+ Tweeter Audio Booster Kit offers one of the easiest and most effective OEM+ audio enhancements available for the 86/GR86/BRZ platform.

• Japanese-made precision audio tuning
  
• Factory-safe and fully reversible
  
• Professional audio enhancement without expensive upgrades

Upgrade your Toyota 86, GR86, or BRZ audio system with the Sequential Sound+ Tweeter Audio Booster Kit and experience clearer, richer sound in minutes.