FORGE MOTORSPORT Audi RS3 8Y Sportback Milltek Exhaust FMSSXAU975

 

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FORGE MOTORSPORT

Audi RS3 8Y Sportback Milltek Exhaust FMSSXAU975

The Milltek Sport Exhaust FMSSXAU975, sold through Forge Motorsport, is a premium OPF/GPF-back Race Non-Resonated exhaust system engineered specifically for the Audi RS3 8Y Sportback (2021–2024) equipped with the legendary 2.5L EA855 EVO turbocharged inline-five engine. 

It replaces the factory exhaust from the gasoline particulate filter (OPF/GPF) rearward while retaining emissions equipment. 

Technical Specifications

• Vehicle: Audi RS3 8Y Sportback (2021–2024)
• Engine: 2.5 TFSI EA855 EVO
• Exhaust Type: OPF/GPF-back
• Configuration: Race Non-Resonated (loudest version)
• Pipe Diameter: 80 mm (3.15 inches)
• Material: T304L aircraft-grade stainless steel
• Manufactured: United Kingdom
• Warranty: Lifetime warranty for the original purchaser (excluding catalytic converters and flex sections). 

Technical Analysis

1. Maximized Exhaust Gas Flow

The large 80 mm mandrel-bent tubing minimizes exhaust backpressure compared with the restrictive factory system.

Benefits include:

• Improved turbocharger efficiency
• Faster turbine acceleration
• Better high-RPM breathing
• More consistent power during repeated acceleration

Although peak horsepower gains on a stock RS3 are modest, the exhaust becomes increasingly beneficial on Stage 1 and Stage 2 tuned vehicles.

2. Authentic Five-Cylinder Sound

The EA855 engine’s 1-2-4-5-3 firing order produces one of the most distinctive exhaust notes available.

This non-resonated system enhances:

• Deep idle tone
• Aggressive mid-range growl
• Iconic Audi five-cylinder warble
• Sharp overrun crackles (where supported by ECU calibration)

Unlike many systems that simply increase volume, Milltek focuses on preserving sound quality.

3. Reduced Restriction

Compared with OEM:

• Larger pipe diameter
• Freer-flowing silencers
• Reduced turbulence
• Less pumping loss

This improves:

• Engine responsiveness
• Turbo spool characteristics
• High-speed acceleration

4. Premium Construction

Milltek’s use of T304L stainless steel provides:

• Excellent corrosion resistance
• Superior weld durability
• Long-term structural integrity
• Resistance to heat cycling

The material also resists discoloration better than lower-grade stainless steel. 

Advantages

Excellent sound engineering

Produces an aggressive yet refined five-cylinder soundtrack without sounding excessively harsh.

Improved throttle response

Reduced exhaust restriction allows the turbo to react more quickly during transient throttle inputs.

High-quality fitment

Milltek systems are widely recognized for OEM-like fitment with accurate hanger placement and minimal installation issues.

Track-capable airflow

The 80 mm design supports significantly higher power levels than stock, making it suitable for future tuning.

Premium materials

Full T304L stainless construction ensures long service life.

Disadvantages

Expensive

This is among the higher-priced stainless steel exhaust options.

Non-resonated design

Cabin drone may be noticeable between approximately 2,000–3,000 rpm depending on driving conditions and transmission gear. Community feedback generally describes it as louder with some drone but still more refined than many track-focused systems. 

Limited gains on a stock vehicle

Without ECU tuning or additional airflow upgrades, most benefits are in sound and responsiveness rather than large horsepower increases.

Comparison Against Competitors

Brand	Sound	Drone	Performance	Weight	Character
Milltek Race Non-Res	5	Medium	4	4	Balanced performance and refinement
Akrapovic Titanium	5	Very Low	5	5	Ultimate premium option with significant weight savings
AWE Track	5	High	4	3	Extremely loud and aggressive
Armytrix Valved	5	Adjustable	4	4	Versatile due to valve control
Remus	4	Low	4	4	Refined European character

Ideal Supporting Modifications

For the best overall package on an Audi RS3 8Y:

• Forge Carbon Fibre Induction Kit
• Forge Intercooler
• Forge Turbo Inlet Pipe
• Stage 1 or Stage 2 ECU calibration
• High-flow intake piping

Together, these modifications improve airflow from intake to exhaust, allowing the EA855 engine to realize greater performance potential. 

Verdict 

The Forge Motorsport / Milltek FMSSXAU975 is one of the strongest stainless-steel exhaust upgrades available for the Audi RS3 8Y Sportback. 

It delivers a meaningful improvement in exhaust flow, a richer and more authentic five-cylinder soundtrack, and OEM-quality construction without sacrificing everyday usability.

Overall ratings:

• Performance: 9.3/10
• Sound Quality: 10/10
• Build Quality: 9.8/10
• Daily Comfort: 8.5/10
• Track Suitability: 9.5/10
• Value for Money: 8.8/10

Overall Score: 9.4/10

This exhaust is particularly well suited for enthusiasts who want a premium, durable system that complements the RS3’s distinctive five-cylinder character while leaving room for future performance upgrades.

FORGE MOTORSPORT

Audi RS3 8Y Sportback Milltek Exhaust FMSSXAU975

 

Nissan GTR R35 Valved Sport Exhaust System

Nissan GT-R R35 Valved Sport Exhaust System (Technical Overview)

The Nissan GT-R R35 Valved Sport Exhaust System is one of the most advanced upgrades available for the legendary VR38DETT 3.8L twin-turbo V6. 

Unlike conventional cat-back exhausts, a valved system gives the driver two distinct personalities at the touch of a button—civilized for daily driving and aggressive for spirited driving or track use.

Core Engineering

The latest premium systems are typically constructed from:

• Aerospace-grade Grade 5 Titanium or T304 Stainless Steel
• Mandrel-bent piping for unrestricted airflow
• 3.0–3.5-inch pipe diameter
• X-pipe or Y-pipe crossover design
• Vacuum or electronically controlled exhaust valves
• High-flow mufflers
• Large titanium or carbon exhaust tips

One example uses a 3.5-inch unrestricted titanium design, vacuum-actuated valves, and weighs approximately 34.5 lb less than the factory exhaust, while remaining a direct bolt-on replacement. 

How the Valves Work

Comfort Mode (Valves Closed)

Exhaust gases pass through:

• Internal mufflers
• Resonators
• Multiple chambers

Result:

• Quiet cold start
• Minimal cabin drone
• Comfortable highway cruising
• Suitable for residential areas

Sport Mode (Valves Open)

The valves create a near-straight exhaust path.

Benefits include:

• Reduced backpressure
• Faster turbo evacuation
• Sharper turbo spool
• More aggressive exhaust tone
• Louder pops and crackles (if tuned)

The transition between modes occurs almost instantly.

Performance Advantages

1. Reduced Backpressure

The VR38DETT relies on efficient turbine flow.

Lower restriction means:

• Improved turbine efficiency
• Less exhaust gas resistance
• Better high-RPM breathing

2. Faster Turbo Response

Reducing pressure after the turbine allows the turbochargers to accelerate more quickly.

Benefits include:

• Faster boost onset
• Better throttle response
• Improved mid-range acceleration

3. Lower Exhaust Gas Temperature

Improved exhaust flow helps reduce heat retention.

Advantages:

• Less thermal stress
• Improved reliability during spirited driving
• Better performance consistency

4. Weight Reduction

Titanium systems commonly save 15–16 kg (around 34.5 lb) compared with the OEM exhaust.

Benefits:

• Better rear weight distribution
• Improved agility
• Reduced overall vehicle mass

Sound Characteristics

Valve Closed:

• Deep
• Refined
• OEM-like comfort
• Minimal drone

Valve Open:

• Exotic high-pitched tone
• Distinct twin-turbo whistle
• Loud downshifts
• Motorsport-inspired sound
• Stronger overrun crackles (with appropriate tuning)

Unlike naturally aspirated V8s, the R35 produces a unique blend of:

• Turbo whistle
• Wastegate sounds
• Deep V6 growl
• High-frequency titanium resonance

Advantages Over Conventional Cat-Back Systems

Feature	Standard Exhaust	Valved Exhaust
Quiet Driving	No	Yes
Track Sound	Moderate	Excellent
Highway Comfort	Moderate	Excellent
Daily Usability	Moderate	Excellent
Driver Adjustable	No	Yes
Premium Value	Medium	High

Compared with Other Premium Brands

Brand	Character
Akrapovic	Refined, lightweight titanium, premium craftsmanship
Armytrix	Aggressive sound with electronic valve control
Fi EXHAUST	Exotic, high-pitched motorsport character
HKS	Deep Japanese tuning sound with strong reliability
Valvetronic Designs	Broad sound range, lightweight titanium construction, significant weight savings, and unrestricted 3.5-inch flow.Â

Possible Disadvantages

• Premium titanium systems can be expensive.

• Installation may require careful alignment due to tight chassis clearances.

• Some very loud configurations may exceed local noise regulations when valves are open.

• On 2017–2023 GT-Rs, the factory electronic exhaust valve system may require proper ECU calibration or valve-controller management when switching to certain aftermarket non-OEM systems to avoid warning lights or drivability issues. 

Best Applications

Ideal for:

• Daily-driven GT-Rs

• Weekend canyon driving

• Track days

• High-horsepower builds (700–1500+ hp)

• Owners seeking both comfort and an aggressive exhaust note

Verdict 

A valved sport exhaust system is among the most versatile upgrades for the Nissan GT-R R35 because it enhances both performance and usability. 

By reducing exhaust restriction, improving turbo response, lowering weight, and allowing instant switching between quiet and aggressive sound profiles, it offers advantages that a fixed cat-back system cannot match.

For enthusiasts building a street-and-track GT-R, a high-quality titanium valved exhaust from a reputable manufacturer represents one of the most balanced modifications, delivering noticeable gains in responsiveness, acoustics, and driving enjoyment without sacrificing everyday comfort.

Nissan GTR R35 Valved Sport Exhaust System