Milltek Filter-back Exhaust for Seat Leon Cupra Leon Mk4 Hatch 300ps (OPF/GPF Equipped) (2021 onwards) – Sharper Sound, Filter Retained
This is Milltek's particulate filter-back system for the Seat Leon Cupra Leon Mk4 Hatch 300ps (OPF/GPF Equipped). It replaces everything downstream of the factory diesel or petrol particulate filter with wider-bore pipework and re-tuned silencers, cutting back pressure and sharpening the exhaust note. The filter itself is left exactly where the manufacturer fitted it, so emissions equipment is unaffected. It's offered in non-resonated or resonated EC approved versions and 2 tailpipe finishes, so you can pick the setup that suits how the car's used.
It's the right choice if you want a sportier sound and a genuine, if modest, flow improvement on a filter-equipped car, without going anywhere near the parts of the system that keep it emissions-compliant.
Specifications
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System Type: Particulate Filter-back
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Pipe Diameter: 80mm (3.15")
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Race System: No
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Fitting Time: approx. 1 to 1.5 hours (Milltek figure)
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
- Fits behind the factory particulate filter, which stays in place
- Choice of 2 tailpipe finishes: Cerakote Black Oval, Polished Oval
- EC approved versions available
- Resonated (quieter) or non-resonated (louder) versions
- Designed, developed and manufactured in the UK by Milltek Sport
Fitment
- Seat Leon Cupra Leon Mk4 Hatch 300ps (OPF/GPF Equipped) (2021 onwards)
Not suitable for: the Seat Leon Cupra Mk4 ST Kombi/Estate 310ps Only (OPF/GPF Equipped), which needs the Milltek Filter-back Exhaust Seat Leon Cupra Mk4 ST Kombi Estate 310ps OPF/GPF 20-24; the Seat Leon Cupra Leon 2.0TSI 245ps (MQB Evo - OPF/GPF Equipped Models), which needs the Milltek Filter-back Exhaust Seat Leon Cupra Leon 2.0TSI 245ps (MQB Evo - OPF/GPF Models) 22+.
Installation
Milltek quotes a fitting time of approx. 1 to 1.5 hours. Some versions: 80mm OPF/GPF Back System (Non Resonated - Louder) - Fits to OE Tips. Some versions: 80mm OPF/GPF Back System (Non Resonated - Louder) - Quad Cerakote Black Ovals (Require Trimming of Plastic Rear Diffuser). Some versions: 80mm OPF/GPF Back System (Non Resonated - Louder) - Quad Polished Ovals (Require Trimming of Plastic Rear Diffuser). Some versions: 80mm OPF/GPF Back System (Resonated) - Fits to OE Tips - ECE Approved. 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: Cerakote Black Oval, Polished Oval. The finish is cosmetic and does not change the sound.
Does it fit the Seat Leon Cupra Mk4 ST Kombi/Estate 310ps Only (OPF/GPF Equipped)?
No. For that car, choose the Milltek Filter-back Exhaust Seat Leon Cupra Mk4 ST Kombi Estate 310ps OPF/GPF 20-24.
Is it road legal?
Some versions are EC approved; check the EC Approved line in the specification for the option you choose.
Do I need a remap?
No. It fits behind the factory particulate filter, so no software changes are needed.
Does it keep the factory particulate filter?
Yes. It fits behind the factory particulate filter, which stays in place.
How long does it take to fit?
Milltek quotes approx. 1 to 1.5 hours.
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.
