Milltek Cat-back Exhaust for Audi S8 D5 4.0 TFSI V8 Saloon/Sedan - Long Wheel Base (Non OPF/GPF US/ROW Models) (2020 onwards) – Sharper Sound, Reduced Back Pressure
This is Milltek's cat-back system for the Audi S8 D5 4.0 TFSI V8 Saloon/Sedan - Long Wheel Base (Non OPF/GPF US/ROW Models). It replaces everything from the factory catalytic converter rearward with wider-bore pipework, a re-profiled mid-pipe and silencers tuned specifically for this platform, cutting back pressure and sharpening the exhaust note. The factory catalytic converter stays in place, so the car's emissions hardware is left as standard. It's offered in non-resonated or resonated versions and 5 tailpipe finishes, so you can pick the setup that suits how the car's used.
It's aimed at owners who want a noticeably different sound and a genuine, if modest, flow improvement without touching anything upstream of the cat: a straightforward bolt-on that doesn't need a remap or any other supporting mods to enjoy.
Specifications
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System Type: Cat-back
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Pipe Diameter: 80mm (3.15")
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EC Approved: No
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Race System: No
Key Features
- Made from T304L aircraft-grade stainless steel, which is anti-magnetic and resists discolouration
- Mandrel-bent pipework keeps a constant diameter through every bend for unrestricted flow
- 80mm (3.15") pipework
- Replaces the standard exhaust from the catalytic converter back, so the factory cat is retained
- Choice of 5 tailpipe finishes: GT-115 Brushed Titanium, GT-115 Burnt Titanium, GT-115 Cerakote Black, GT-115 Polished, JET-115 Carbon Fibre
- Resonated (quieter) or non-resonated (louder) versions
- Designed, developed and manufactured in the UK by Milltek Sport
Fitment
- Audi S8 D5 4.0 TFSI V8 Saloon/Sedan - Long Wheel Base (Non OPF/GPF US/ROW Models) (2020 onwards)
Not suitable for: the Audi S8 D5 4.0 TFSI V8 Saloon/Sedan - Standard Wheel Base (Non OPF/GPF US/ROW Models), which needs the Milltek Filter-back Exhaust Audi S8 D5 4.0 TFSI V8 Saloon OPF/GPF UK Euro 20+.
Installation
Some versions: Non-Resonated Cat Back Back System (Twin 80mm) with GT-115 Brushed Titanium Trims (Does Not Require Cutting of the OE System) - Louder. Some versions: Non-Resonated Cat Back Back System (Twin 80mm) with GT-115 Burnt/Blue Titanium Trims (Does Not Require Cutting of the OE System) - Louder. Some versions: Non-Resonated Cat Back Back System (Twin 80mm) with GT-115 Cerakote Black Trims (Does Not Require Cutting of the OE System) - Louder. Some versions: Non-Resonated Cat Back Back System (Twin 80mm) with GT-115 Polished Trims (Does Not Require Cutting of the OE System) - Louder. We recommend professional fitting on a ramp. Once fitted, check the tailpipe alignment and re-check all clamps after the first few hundred miles.
What's the difference between the resonated and non-resonated versions?
The resonated version adds extra silencing for a quieter, more refined tone. The non-resonated version leaves it out, so it is louder and more aggressive.
Which tailpipe finishes are available?
You can choose from: GT-115 Brushed Titanium, GT-115 Burnt Titanium, GT-115 Cerakote Black, GT-115 Polished, JET-115 Carbon Fibre. The finish is cosmetic and does not change the sound.
Does it fit the Audi S8 D5 4.0 TFSI V8 Saloon/Sedan - Standard Wheel Base (Non OPF/GPF US/ROW Models)?
No. For that car, choose the Milltek Filter-back Exhaust Audi S8 D5 4.0 TFSI V8 Saloon OPF/GPF UK Euro 20+.
Is it road legal?
Milltek does not list EC approval for this part. Any exhaust used on the road must still meet noise and emissions rules, so check the requirements where you live.
Do I need a remap?
No. It fits behind the factory catalytic converter, so no software changes are needed.
Does it keep the factory catalytic converter?
Yes. It fits behind the factory catalytic converter, which stays in place.
What is it made from?
T304L aircraft-grade stainless steel, which is anti-magnetic and resists discolouration better than lower grades.
Is there a warranty?
Yes. Milltek products are covered against defects in materials and workmanship. Contact us with your order number if you have a problem.
