Milltek Cat Back Exhaust - BMW F8X M3/M4 OPF (ECE approved)

QT Parts is a Finnish online store.

Our warehouse is located in Nokia, Finland.

You can collect your order directly from us if needed. Simply select “Pickup” at checkout.

Pay securely with multiple payment methods, including invoice and installment plans through Klarna.

The delivery time for products in stock is 1-5 business days. We ship worldwide.

If the product is not in stock and it is a pre order product, the average delivery time is 5-21 business days. If the product has a longer delivery time than previously announced, we will be in touch. International orders may be subject to VAT, import duties, and customs fees upon arrival in the destination country.

Terms for product returns:

• You must return the ordered products within 14 days of receiving
• The products must be unused and without damages
• Commission fee for handling returns is 21,90€
• For product returns, the customer is in charge of the return costs. Only door to door service (Express)
• Shipping costs are not refunded

For international orders sales are final and non-refundable. Once an order is placed, it cannot be canceled or returned. By placing an order, you acknowledge and agree to these terms.

Return address: QT Parts, Vasarakatu 8B, 37150 Nokia, Finland.

Pre order / made-to-order products

If the product you have ordered is a pre order or made-to-order item, it is not subject to the 14-day right of withdrawal or return under consumer protection laws, as the product is manufactured or sourced specifically based on the customer’s individual order.

If you wish to cancel your order before receiving the product, we will refund 50% of the total order amount.

This condition applies to the following product categories:

• Suspension
• Engine Tuning
• Engine Parts
• Exhaust Systems
• Fueling
• Turbochargers/superchargers
• Drivetrain
• ECE-approved Downpipes

All of the above products are manufactured or sourced individually based on the customer’s order, and therefore cannot be returned after delivery, unless the product has a manufacturing or material defect.

In the event of such a defect, the standard liability for defects as provided by consumer protection legislation shall apply.

The Milltek Sport Cat Back Exhaust System offers a significant improvement in sound quality, appearance and driving experience for the BMW F8X series M3 and M4 models. The 2019-2020 models equipped with OPF/GPF filters are notoriously muffled by the standard system, and Milltek has developed a system for this generation that restores the car's sound to the sportiness it deserves - with quality, balance and without excessive noise.

The Cat Back system replaces the exhaust system from the OPF/GPF filters backwards, producing a cleaner sound, better flow efficiency and a more intense driving feel.

Sound quality that suits the nature of the F8X generation

The S55 engine is known for its sharp, rev-sensitive nature – but the OPF models significantly quieten it down. The Milltek Cat Back frees the engine:

• Deeper bass tone at idle

• Sporty, rich midrange

• Clearer and more dynamic sound at high revs

• No annoying hum or resonance when driving on the road

• ECE approved

The soundscape restores the personality that many drivers feel they have lost with the factory OPF system.

Direct bolt-on installation

The system fits perfectly into the original mounting points:

• No need to modify vehicle structures

• Perfect compatibility with car valve control

• OEM-quality fit and finish

Milltek's meticulous design ensures that installation is simple and the end result looks factory-made – but sounds significantly better.

304L Aircraft Grade Stainless Steel

The entire system is made of high-quality 304L aircraft steel, which provides:

• Exceptional corrosion resistance

• Long service life even under heavy loads

• Impeccable welding and surface work

• Excellent flow properties throughout the entire rev range

This material is standard in premium performance systems.

Output options and configurations

Milltek offers several visual and acoustic options:

• Polished steel

• Black ceramics

• Titanium

• Carbon fiber-coated options

The configurations allow you to fine-tune the volume and tone to your own preference.

Compatibility: BMW F8X M3/M4

This Cat Back system fits the following OPF/GPF models (2019-2020 facelift models only):

• BMW M3 F80

• BMW M3 Competition F80

• BMW M3 CS F80

• BMW M4 Coupe F82

• BMW M4 Convertible F83

• BMW M4 Competition (F82/F83)

• BMW M4 (F82)

All versions: rear-wheel drive, manual & DCT.