RM Engineering GT4+ Aero Kit for BMW F8X M3 / M4

Engineered for Maximum Performance. Inspired by BMW Motorsport. Proven on Track.

The Ridgeline Motorsport GT4+ Aero Kit is our most comprehensive aerodynamic package for the BMW F8X platform.

Developed from the visual and aerodynamic foundation of the BMW F82 M4 GT4 race car, the GT4+ system evolves beyond the limitations of the original GT4 rulebook. Each component was redesigned using real-world track experience to increase aerodynamic performance while maintaining a balanced relationship between front and rear downforce.

Designed for serious track-day drivers, time attack competitors, and high-performance street builds, the complete GT4+ package combines a reinforced front lip, tunneled front splitter, GT4 canards, and a chassis-mounted rear wing into one integrated aerodynamic system.

Vehicle Fitment

Designed for compatible BMW F8X M models, including:

• BMW F80 M3 Sedan
• BMW F82 M4 Coupe
  

Please confirm your vehicle model, bumper configuration, trunk configuration, and competition-class requirements before ordering.

Track-Proven Development

The GT4+ Aero Kit was developed and tested on road-going BMW F8X vehicles equipped primarily with bolt-on modifications.

Testing results were achieved without extensive vehicle weight reduction and while using 275/35R18 200TW street-class tires.

Recorded F-Chassis Results

Super Lap Battle 2025 — Circuit of the Americas

• Fastest BMW in class, excluding two Toyota Supras

WeatherTech Raceway Laguna Seca

• Best recorded lap: 1:34.341

Global Time Attack Finals — Buttonwillow CW13

• Fourth place
• Best recorded lap: 1:50.940
• Fastest BMW in class, excluding three Toyota Supras

Real-world testing, competition use, and continuous development remain central to every Ridgeline Motorsport aerodynamic product.

Included Components

GT4+ Front Lip

The GT4+ Front Lip features a reinforced design developed to create a sealed front aerodynamic plane when paired with the GT4+ Tunneled Splitter.

The front lip may also be installed without the lower splitter. However, using the lip without the splitter may reduce its structural support and service life, particularly during track use or contact with road surfaces.

Front Lip Features

• Reinforced GT4-derived design
• Designed to integrate with the GT4+ Tunneled Splitter
• Creates a cleaner transition between the bumper and splitter
• May be installed separately
• Hardware included

GT4+ Tunneled Front Splitter

The GT4+ Tunneled Splitter combines the front lip and lower splitter into a two-piece aerodynamic system.

An integrated airflow channel helps maintain airflow toward the factory lower oil cooler, while the molded tunnel increases aerodynamic surface control, structural rigidity, and front-end performance.

Splitter Features

• Two-piece front lip and splitter system
• Integrated airflow channel for the lower oil cooler
• One-piece molded aerodynamic tunnel
• Designed to increase front-end downforce
• Reinforced construction for improved rigidity
• Installation hardware included
• Minor modification of OEM vehicle components required

Aluminum Skid Block Kit

An aluminum skid block kit is available 

The skid blocks help protect the lower splitter surface from contact with pavement, curbing, driveways, and track surfaces.

OEM GT4 1:1 Canards

The included GT4 canards replicate the geometry and positioning of the OEM BMW M4 GT4 components.

They are designed to work with the GT4+ front aero system to improve front-end aerodynamic response, particularly during medium- and high-speed driving.

Canard Features

• OEM GT4 geometry
• Designed to improve front-end aerodynamic balance
• Supports increased high-speed stability
• Integrates with the GT4+ front lip and splitter system
• Installation hardware included

GT4+ Chassis-Mounted Rear Wing

The GT4+ Rear Wing uses a redesigned chassis-mounted support system developed to address the potential water-leak concerns associated with the original GT4 trunk-mounting configuration.

The mounting system maintains structural support while allowing aerodynamic loads to be transferred through reinforced mounting locations.

The GT4+ wing foil is larger than the OEM GT4 wing because it is not restricted by the original GT4 vehicle regulations. The increased surface area is designed to generate additional rear downforce while maintaining an efficient aerodynamic profile.

Rear Wing Features

• Chassis-mounted rear wing system
• Redesigned mounting solution
• Developed to reduce the risk of trunk water intrusion
• Larger wing foil (1600mm) than the OEM M4 GT4 wing
• Increased aerodynamic surface area
• Designed to generate additional rear downforce
• Maintains structural rigidity under aerodynamic load
• Installation hardware included

Why Choose the GT4+ Aero Kit?

• Developed specifically for the BMW F8X M3 and M4
• Inspired by BMW Motorsport GT4 aerodynamics
• Increased front and rear aerodynamic performance
• Designed as a balanced complete aero package
• Tested through real-world track and time attack competition
• Modular construction allows components to be purchased separately
• Suitable for dedicated track cars and performance-focused street builds
• Installation hardware included

Competition Class Notice

The GT4+ Aero Kit was developed with commonly used Global Time Attack Street Class and GRIDLIFE Street Mod aerodynamic limitations in mind.

Competition rules may change between seasons, and eligibility depends on the vehicle’s complete configuration rather than the aero kit alone. Drivers are responsible for reviewing the latest rules and confirming eligibility with the event organizer before competition.

Ridgeline Motorsport does not guarantee class eligibility for every vehicle, event, or future ruleset.

Installation

Professional installation is strongly recommended.

Installation may require:

• Removal of exterior body panels
• Drilling of mounting holes
• Cutting or modification of certain OEM components
• Alignment of the front splitter and canards
• Reinforcement of rear-wing mounting locations
• Adjustment of the front and rear aero balance

Test-fit and align every component before drilling, cutting, or permanently securing the kit.

The complete kit is recommended for the best front-to-rear aerodynamic balance.

Installation Guides

GT4+ Splitter Installation Guide

View the GT4+ Splitter Installation Guide

GT4+ Kit Installation Videos

Watch GT4+ Kit Installation Video — Part 1

Watch GT4+ Kit Installation Video — Part 2

Aerodynamic Product Disclaimer

Aerodynamic performance will vary based on vehicle speed, ride height, suspension setup, alignment, wing angle, splitter extension, tire selection, track conditions, and the vehicle’s complete aerodynamic configuration.

Aerodynamic components can place additional loads on the bumper, chassis, trunk, mounting hardware, and surrounding vehicle structure. The installer is responsible for confirming that all mounting points are properly installed, reinforced, and suitable for the intended use.

Impacts involving chassis-mounted aerodynamic components may transfer force into the vehicle and cause additional damage.

Ridgeline Motorsport is not responsible for vehicle damage resulting from improper installation, impacts, road hazards, accidents, misuse, competition use, or failure to inspect and maintain the components and mounting hardware.