Quick recommendations
- Stage 1 3.0 TFSI: No supporting hardware required; approximately 400–410hp and 470–480 lb-ft in our experience.
- Stage 1 transmission: TCU calibration advised to handle the extra torque and improve shift quality.
- Low-cost intake upgrade: RacingLine high-flow replacement filter.
- Complete intake: Eventuri or RacingLine carbon intake – both are excellent, so choose according to preference.
- Stage 2: Downpipe, complete intake and uprated intercooler, with suitable ECU and TCU calibration.
- Hard use: Uprated intercooler strongly advised because the standard car can heat-soak during repeated pulls.
- Exhaust: Cat-back mainly changes sound and appearance; the downpipe/high-flow catalyst provides most of the performance gain.
- Stage 2 downpipe gain: Approximately 10–20hp on a correctly tuned car.
- Catch can: Most worthwhile on harder-driven and higher-boost cars.
- Atmospheric dump valve: Primarily a sound modification.
Important: The performance and tuning advice below relates primarily to the Audi S5 B9 fitted with the 3.0 TFSI petrol engine. Always check the engine and individual product fitment before ordering, particularly on facelift UK and European cars.
Audi S5 B9 performance parts buying guide
The 3.0 TFSI Audi S5 B9 responds extremely well to software alone, which means there is no need to start replacing hardware simply because you want a Stage 1 tune.
A sensible upgrade path is to tune the standard car first, then add intake, cooling and exhaust-flow upgrades as the power target and level of use increase.
For exterior upgrades, browse our Audi S5 B9 Body Kits & Styling collection.
Audi S5 B9 Stage 1 power
On a healthy 3.0 TFSI petrol S5 B9, we would normally expect approximately:
This is achievable without changing the intake, intercooler or exhaust system.
Stage 1 is therefore one of the best value modifications for the car because the original hardware already has enough capacity for a substantial increase in power and torque.
Does Stage 1 need any hardware?
No.
A healthy standard intake, intercooler and exhaust can support a normal Stage 1 calibration.
Optional supporting upgrades can still improve sound, appearance, temperature control or future upgrade potential, but they are not required simply to run Stage 1.
Is a TCU tune worthwhile at Stage 1?
Yes. We advise a TCU calibration alongside Stage 1 because of the substantial increase in engine torque.
The RacingLine OEM+ ECU and ZF8 TCU software package is designed to coordinate engine and transmission calibration.
A suitable TCU tune can improve:
- Torque handling
- Shift quality
- Shift response
- Gear-selection strategy
- Manual-mode behaviour
- Launch-control behaviour where supported
We consider it worthwhile even at Stage 1 rather than waiting until the car moves to Stage 2.
What does an S5 B9 Stage 2 setup need?
For a proper Stage 2 3.0 TFSI setup, we would normally use:
- High-flow downpipe
- Performance intake
- Uprated intercooler
- Stage 2 ECU calibration
- TCU calibration
The aim is to reduce restriction and control intake temperatures while the turbocharger is being worked harder.
Eventuri versus RacingLine intake
Both the Eventuri and RacingLine carbon intake systems are excellent options for the S5 B9.
In our experience, there is no major reason to choose one over the other from a performance point of view. The decision is largely down to which design, carbon finish and overall look you prefer.
Eventuri carbon intake
The Eventuri carbon intake replaces the restrictive original intake path with a sealed carbon-fibre system.
Eventuri quotes a manufacturer-tested gain of approximately 13–17bhp and 15–20 lb-ft. These are Eventuri's figures rather than Wayside dyno results.
RacingLine carbon intake
The RacingLine carbon intake retains part of the original airbox while adding a carbon lid, high-flow filter and revised front air scoop.
It is another very well-designed option and performs similarly in real-world use.
Best budget intake upgrade
If you do not want to spend over £1,000 on a complete carbon intake, a high-flow replacement panel filter is a worthwhile low-cost first step.
The RacingLine high-flow replacement filter fits into the original airbox.
In our experience, you can gain a couple of horsepower while retaining the complete factory intake appearance and refinement.
Does the Audi S5 B9 have an intercooler?
Yes. The 3.0 TFSI B9 S5 uses a front-mounted air-to-air intercooler.
The intercooler cools the compressed air leaving the turbocharger before it enters the engine.
As boost pressure increases, the turbocharger generates more heat, making intercooler efficiency increasingly important.
Does Stage 1 need an intercooler?
No. The standard intercooler is adequate for a normal Stage 1 road car.
However, an uprated intercooler becomes worthwhile if the car is regularly driven hard, particularly during warm weather.
Why upgrade the intercooler?
The standard S5 can get quite hot during repeated full-load acceleration.
Once the intercooler and surrounding cooling system heat-soak, intake-air temperature rises and performance can become less consistent.
This is most noticeable during:
- Repeated dyno pulls
- Hard fast-road driving
- Hot summer weather
- Track use
- Stage 2 operation
For those reasons, we strongly recommend an uprated intercooler for Stage 2 or repeated hard use.
Forge Motorsport intercooler
The Forge Motorsport B9 S4/S5 intercooler is a direct front-mounted cooling upgrade.
Forge specifies a 650 × 420 × 50mm bar-and-plate core and states that it provides a 128% increase in frontal area and internal volume compared with the original cooler.
Those are manufacturer specifications, but they illustrate the substantial increase in cooling capacity available compared with the factory intercooler.
Audi S5 B9 exhaust upgrades
For most owners, the first exhaust decision is whether the goal is sound or performance.
Cat-back exhaust
A Milltek cat-back is primarily a sound and appearance upgrade.
It changes the exhaust tone and gives the car a more sporting character, but we would not expect a substantial horsepower increase from the rear system alone.
Downpipe and catalytic-converter section
The main exhaust-flow restriction is further forward.
Replacing the standard catalyst/downpipe section with a freer-flowing version gives a much more meaningful performance benefit once the ECU is calibrated appropriately.
Milltek downpipe options
The Milltek S5 B9 downpipe is available with either:
- High-flow sports catalyst
- De-cat section
The Milltek downpipe can connect to either the original exhaust system or a Milltek Sport cat-back.
For a road-going vehicle, we would choose the sports-cat configuration. The de-cat option should be treated as an off-road or motorsport component.
How much power does an S5 B9 downpipe add?
On a correctly calibrated Stage 2 3.0 TFSI, we would expect approximately 10–20hp from replacing the restrictive standard catalyst/downpipe section.
The exact result depends on:
- ECU calibration
- Fuel quality
- Intake system
- Intercooler efficiency
- Ambient temperature
- Condition of the engine and turbocharger
Do I need a sports exhaust for Stage 1?
No.
The original exhaust system is perfectly adequate for Stage 1.
Fit a cat-back at this stage if you want more sound, or fit the complete performance exhaust hardware if you already know you intend to move to Stage 2 later.
Catch cans and oil management
Catch-can and uprated oil-management systems become more relevant as the car is driven harder and boost pressure increases.
They are not something we consider essential for a normal standard or lightly used Stage 1 road car.
They are more worthwhile for:
- Higher-boost cars
- Hard-driven road cars
- Track use
- Owners looking to reduce oil vapour entering the intake system
RacingLine oil management system
The RacingLine B9 3.0 TFSI Oil Management System replaces the factory PCV arrangement with a dedicated separator and catch-can system.
RacingLine states that the system is designed to reduce oil and moisture contamination entering the intake tract.
Forge catch tank
The Forge Motorsport S4/S5 B9 catch tank is another purpose-designed option.
Forge positions it specifically for reducing oil deposits, fuel vapour and moisture being recirculated into the engine.
For most normal road cars, we would prioritise the core tuning hardware first and consider a catch can when the car is being pushed harder.
Forge atmospheric dump valve
The Forge atmospheric dump valve is primarily a sound modification.
It vents boost pressure to atmosphere when the throttle closes, giving the characteristic audible dump-valve sound.
Forge also uses a billet piston-based design rather than the original diaphragm-style arrangement, but for a healthy road car we would fit the atmospheric version mainly because the owner wants the sound.
Do tuned S5 B9s need uprated ignition coils?
Not normally.
The standard ignition coils work perfectly well on healthy Stage 1 and Stage 2 cars.
We would not replace a complete healthy set purely because the car has been remapped.
If a coil begins failing and causing a misfire, however, it is reasonable to replace it with an uprated unit such as:
Always diagnose a misfire properly before replacing parts, as plugs, fuelling or boost issues can produce similar symptoms.
RacingLine body brace
The RacingLine B9 body brace replaces the lighter factory front brace with a more rigid billet-aluminium component.
The difference on a normal road car is relatively subtle, but it can improve:
- Front-end chassis stiffness
- Steering response
- The connected feel of the front suspension
It is a nice finishing modification for an enthusiast looking to sharpen the chassis rather than a transformative first handling upgrade.
Best S5 B9 upgrade path
Standard road car
- High-flow panel filter if desired
- Cat-back exhaust for sound
- Body and styling upgrades according to preference
Stage 1 road car
- Stage 1 ECU calibration
- TCU calibration advised
- No supporting hardware required
- Optional intake for sound, appearance and improved airflow
Expected output in our experience: approximately 400–410hp and 470–480 lb-ft.
Stage 2 road car
- High-flow downpipe / sports cat
- Eventuri or RacingLine intake
- Forge intercooler
- Stage 2 ECU calibration
- TCU calibration
Hard-driven or track-focused car
In addition to the appropriate Stage 1 or Stage 2 hardware, consider:
- Uprated intercooler
- Catch-can / oil-management system
- Body brace
- More frequent inspection and servicing
Frequently asked questions
How much power does a Stage 1 Audi S5 B9 make?
We normally see approximately 400–410hp and 470–480 lb-ft from a healthy 3.0 TFSI petrol car.
Does Stage 1 need an intake?
No. The original intake can support Stage 1.
Does Stage 1 need an intercooler?
No, but an uprated intercooler is worthwhile for repeated hard use or hot weather.
Should I tune the ZF8 gearbox at Stage 1?
Yes. We recommend TCU calibration to improve torque handling, shift response and overall transmission behaviour.
Eventuri or RacingLine intake?
Both are excellent. In our experience they perform similarly, so choose the design and appearance you prefer.
Is a panel filter worth fitting?
Yes. It is a simple low-cost upgrade that can provide a small airflow and power improvement while retaining the original airbox.
Does the S5 B9 have an intercooler?
Yes. The 3.0 TFSI uses a front-mounted air-to-air intercooler.
When should the intercooler be upgraded?
We strongly advise it for Stage 2 and for cars regularly subjected to repeated hard acceleration or track use.
Does a cat-back add much power?
No. It is mainly a sound and appearance modification.
What exhaust part provides the most power?
The greatest restriction is around the factory catalyst/downpipe section, so replacing this as part of a Stage 2 setup provides the more meaningful gain.
How much power can a downpipe add?
Approximately 10–20hp is a realistic contribution on a correctly tuned Stage 2 car.
Does every tuned S5 need a catch can?
No. We consider them more relevant for higher-boost, harder-driven and track-used cars.
Does the Forge atmospheric valve add power?
We mainly regard it as a sound modification.
Do I need uprated ignition coils?
No. Healthy factory coils are perfectly adequate. Upgrade them if an original coil has failed or you specifically want the aftermarket replacement.
Is the RacingLine body brace worthwhile?
It gives a subtle increase in front-end stiffness and steering response rather than a dramatic transformation.
Audi S5 B9 Body Kits & Styling
For front splitters, side skirts, rear valances, canards and other exterior upgrades, browse our Audi S5 B9 Body Kits & Styling collection.
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Vendor:Racingline
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Vendor:Racingline
Vendor:Milltek
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Vendor:Forge Motorsport
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