BMW M135i 2015

Service Completed: Mid Resonator & Backbox Delete Upgrade

At MIJ Exhaust Ltd, we recently carried out a custom exhaust upgrade on this BMW 135i 2015 3.0L Petrol, designed to unleash more of the engine’s sound and give the car a much more aggressive presence on the road.

For this build, we completed a mid resonator delete along with a backbox delete, allowing the exhaust system to flow more freely and produce a louder, deeper and more responsive tone. The upgrade brings out the natural character of the 3.0L engine, delivering a sharper exhaust note under acceleration while adding more crackles and overall presence throughout the rev range.

To finish the setup off, we fitted single black slash cut exhaust tips on both sides, giving the rear of the vehicle a clean and stealthy performance-inspired appearance that perfectly suits the styling of the 135i.

As with all of our custom exhaust systems, the work was fabricated and installed entirely in-house using high-quality materials and precision fabrication techniques to ensure excellent fitment, durability, and a clean final finish.

We’ve also got a full sound test video of this build so you can hear exactly how this upgraded 135i now sounds.

Check out the video and let us know what you think of this BMW transformation.
https://www.instagram.com/p/DXmxnA7jXH8/

Why Choose a Custom MIJ Exhaust?

No two vehicles—and no two customers—are alike. That’s why every exhaust system we build is custom-made on the vehicle for the perfect fit, tone, and performance.

Whether you’re after:

A sportier, more aggressive sound,

A performance-focused setup, or

A refined, OEM-style tone,

—we tailor the design specifically to your goals.

More Than Just Custom Builds

We provide all types of exhaust services, including:

Exhaust repairs and leak fixes

Section replacements

Welding cracks and fault correction

Tailpipe upgrades and cosmetic enhancements

Small adjustments and one-off jobs