Milltek Cat Back Exhaust - BMW F20/F21 M135i RWD 2012-2016

The delivery time for products in stock is 1-3 business days.

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.

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 (outside of Europe) 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 is designed for BMW M135i drivers who want to improve the sound, flow and overall driving experience of their car while maintaining the original drivability. While the factory system restricts sound and exhaust flow, Milltek's Cat Back solution unleashes the character of the N55 engine in a controlled and high-quality way.

The Cat Back system replaces the section of the exhaust system after the catalytic converter and brings with it a clearly sportier and richer sound.

Sporty and balanced N55 sound profile

Milltek has tuned this system specifically for the M135i's 3.0-liter N55 engine:

• Deeper and fuller sound at idle

• Clearer and more powerful sound during acceleration

• Sporty yet controlled sound at high revs

• No annoying resonance or drone at cruising speeds

The sound profile emphasizes the engine's character without compromising daily driving comfort.

Improved flow and ride feel

Milltek Cat Back Exhaust System:

• reduces exhaust back pressure

• supports engine's sensitive throttle response

• improves the overall driving experience

The freer-flowing structure also supports moderate power upgrades.

Easy bolt-on installation

• to fit directly into the car's original mounting points

• for installation without welding or permanent changes

• compatible with rear-wheel drive (not xDrive) models

OEM-level fit ensures effortless installation and a clean finish.

304L Aircraft Grade Stainless Steel

The entire system is made of high-quality 304L grade stainless steel , which offers:

• excellent corrosion and heat resistance

• long service life

• carefully finished TIG welds

The choice of materials meets Milltek's high quality standards.

Fit

• BMW M135i 3-door (F20)

• BMW M135i 5-door (F21)

Engine: 3.0 Turbo (N55)
Rear-wheel drive
No xDrive
Model years 2012–2016