What is a G37 Diffuser?
A G37 diffusers is a panel installed on the lower rear bumper of your car, designed to channel airflow efficiently under and away from the vehicle. On the Infiniti G37, especially the coupe and sedan models from 2008–2013, a diffuser serves both aesthetic and aerodynamic purposes.
In performance cars, diffusers reduce drag and lift, improving stability at high speeds. In style-focused builds, they give the car a sporty, aggressive rear-end look. The G37, with its naturally aggressive body lines, benefits immensely from the right diffuser choice.
Why Install a Diffuser on Your G37?
Let’s break down the real-world benefits:
1. Improved Aerodynamics
The diffuser helps manage how air exits the underside of the car, reducing turbulence and allowing for better airflow management, which can translate into slightly better high-speed handling.
2. Sportier Appearance
This is the most common reason G37 owners opt for a diffuser. A rear diffuser immediately makes the car look lower, wider, and more performance-oriented.
3. Increased Downforce (In Some Models)
High-performance diffusers create negative lift (downforce), improving traction—especially useful if your G37 is used for track days or spirited driving.
4. Aftermarket Exhaust Fitment
Some aftermarket diffusers are designed to fit around or accommodate larger aftermarket exhaust tips, giving a clean and aggressive rear profile.
Types of G37 Diffusers
When shopping for a diffuser, it helps to know your options:
1. Bolt-On OEM Style
- Designed to fit without modification
- Matches factory aesthetics
- Best for daily drivers
2. Aggressive Aftermarket Style
- Comes with deeper fins and aggressive cuts
- Often made from carbon fiber or ABS plastic
- Ideal for show cars or performance builds
3. Track-Spec Diffusers
- Functional diffusers focused on performance
- Require custom mounting
- Built from lightweight materials like aluminum or race-grade composites
4. Carbon Fiber G37 Diffuser
- Premium look and lightweight
- Higher price tag but excellent for show builds
- Resists UV and weather better than ABS plastic
Top 5 Best G37 Diffusers in 2025
Here are the most highly-rated and enthusiast-approved options on the market right now:
1. Stillen Rear Diffuser for G37 Coupe
- Material: Polyurethane
- Fitment: 2008–2013 G37 Coupe
- Pros: Excellent fitment, OEM-quality, reputable brand
- Cons: Not the most aggressive look
2. Fly1 Motorsports Carbon Fiber G37 Diffuser
- Material: Real Carbon Fiber
- Pros: Show-stopping finish, lightweight
- Cons: Pricey, limited availability
3. Duraflex GT500 Style Rear Diffuser
- Material: Fiberglass-reinforced plastic
- Pros: Race-inspired design, affordable
- Cons: May require slight modifications
4. IKON Motorsports Rear Bumper Lip Diffuser
- Material: ABS Plastic
- Pros: Budget-friendly, decent finish
- Cons: Fitment can vary; recommend professional install
5. AeroFunction Track Spec G37 Diffuser
- Material: Lightweight race composite
- Pros: Built for performance
- Cons: Requires drilling and mounting
How to Install a G37 Diffuser (Step-by-Step)
Most bolt-on G37 diffusers can be installed with basic tools in 1–2 hours. Here’s a simplified guide:
Tools You’ll Need:
- Screwdriver or drill
- Jack & jack stands (optional but helpful)
- Trim removal tools
- Fasteners (often included)
Step-by-Step Guide:
- Clean the Rear Bumper
Ensure the surface is clean and dry to avoid fitment issues. - Remove OEM Lower Bumper (if needed)
Some diffusers are overlays; others require removing the stock valance. - Test Fit the Diffuser
Always align the diffuser before drilling or fastening. - Mark Drill Points (if applicable)
If no OEM mounting points exist, mark your drill spots carefully. - Attach the Diffuser
Use screws, bolts, or provided clips. For carbon fiber models, use washers to avoid cracks. - Double-Check Alignment
Once secure, step back and ensure it sits flush and even. - Optional: Paint or Wrap Matching Trim
For a seamless look, paint-match or wrap adjacent trim pieces.
Where to Buy the Best G37 Diffusers
Recommended Sources:
- Z1 Motorsports – Trusted for Infiniti/Nissan parts
- Stillen.com – Brand-direct supplier
- eBay Motors – Great for deals, but be cautious with sellers
- Fly1Motorsports.com – Ideal for premium carbon fiber options
- Amazon – Has several ABS and fiberglass options
Pro Tip:
Always check user reviews and look for real-installed photos. Fitment varies by trim (sedan vs coupe), so double-check compatibility!
FAQs About G37 Diffusers
Q1. Will a G37 coupe diffuser fit on a sedan?
No. The bumper designs are different. Coupe and sedan diffusers are not interchangeable without heavy modification.
Q2. Do diffusers really improve performance?
Yes, but only to a minor degree on daily cars. The main benefit is aesthetic, though track-spec diffusers do improve airflow and stability.
Q3. Can I install a diffuser myself?
Yes. Most are DIY-friendly with basic tools. However, if drilling is required or you’re dealing with carbon fiber, professional install is safer.
Q4. How much does a G37 diffuser cost?
Prices range from $100 (ABS plastic) to $600+ (carbon fiber) depending on material and brand.
Q5. Is a diffuser the same as a rear lip?
Not exactly. A rear lip spoiler sits higher, often on the trunk, while a diffuser is mounted on the lower rear bumper.
Final Thoughts
A G37 diffuser is one of the most impactful upgrades for your Infiniti—combining style, mild aerodynamic improvements, and compatibility with other mods like exhaust systems. Whether you’re going for a track-ready look, show-car finish, or just want that aggressive edge, there’s a perfect diffuser out there for your build.
