Milltek Cat-back Exhaust for BMW 3 Series G20 & G21 M340i XDrive Saloon & Touring Models (OPF/GPF Models Only) Pre LCI (2019-2025) – Sharper Sound, Reduced Back Pressure
This is Milltek's cat-back system for the BMW 3 Series G20 & G21 M340i XDrive Saloon & Touring Models (OPF/GPF Models Only) Pre LCI. 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 2 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: check the notes on each version below, as some need supporting software.
Specifications
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System Type: Cat-back
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Pipe Diameter: 76.2mm (3")
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EC Approved: No
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Race System: Yes
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Fitting Time: approx. 2 to 2.5 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
- 76.2mm (3") pipework
- Replaces the standard exhaust from the catalytic converter back, so the factory cat is retained
- Choice of 2 tailpipe finishes: GT-100 Black, GT-100 Polished
- Designed, developed and manufactured in the UK by Milltek Sport
Fitment
- BMW 3 Series G20 & G21 M340i XDrive Saloon & Touring Models (OPF/GPF Models Only) Pre LCI (2019-2025)
- BMW 4 Series G22 M440i Coupe (OPF/GPF Equipped Models Only) Pre LCI (2020-2025)
Not suitable for: the BMW 3 Series G20 M340i Sedan inc Xdrive (North American/ROW Models Only) Pre LCI, which needs the Milltek Cat-back Exhaust BMW 3 Series G20 M340i Sedan inc Xdrive (North American & ROW Only) Pre LCI 21-25; the BMW 3 Series F80 M3, M3 Competition & M3 CS Saloon (OPF/GPF Models Only), which needs the Milltek Cat-back Exhaust BMW 3 Series F80 M3, M3 Comp M3 CS Saloon OPF/GPF 19-20; the BMW 3 Series F80 M3 & M3 Competition Saloon (Non OPF/GPF Models Only), which needs the Milltek Cat-back Exhaust BMW 3 Series F80 M3 M3 Comp Saloon Non OPF/GPF 14-18.
Installation
Milltek quotes a fitting time of approx. 2 to 2.5 hours. Some versions: OPF/GPF Bypass, fits to OE Trims - Requires Stage 2 ECU Software. Some versions: OPF/GPF Bypass, Quad GT-100 Black Trims - Requires Stage 2 ECU Software. Some versions: OPF/GPF Bypass, Quad GT-100 Polished Trims - Requires Stage 2 ECU Software. We recommend professional fitting on a ramp. Once fitted, check the tailpipe alignment and re-check all clamps after the first few hundred miles.
Which tailpipe finishes are available?
You can choose from: GT-100 Black, GT-100 Polished. The finish is cosmetic and does not change the sound.
Will it fit the BMW 4 Series G22 M440i Coupe (OPF/GPF Equipped Models Only) Pre LCI?
Yes. Milltek lists this part for the BMW 4 Series G22 M440i Coupe (OPF/GPF Equipped Models Only) Pre LCI as well as the other models in the fitment list above.
Does it fit the BMW 3 Series G20 M340i Sedan inc Xdrive (North American/ROW Models Only) Pre LCI?
No. For that car, choose the Milltek Cat-back Exhaust BMW 3 Series G20 M340i Sedan inc Xdrive (North American & ROW Only) Pre LCI 21-25.
Is it road legal?
Milltek lists this as a race part without EC approval, so it is intended for off-road and competition use.
Do I need a remap?
Some versions do. Milltek notes: "OPF/GPF Bypass, fits to OE Trims - Requires Stage 2 ECU Software". Check the notes for the version you choose.
Does it keep the factory catalytic converter?
Yes. It fits behind the factory catalytic converter, which stays in place.
How long does it take to fit?
Milltek quotes approx. 2 to 2.5 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.
