BMW M135 (F70) Quad Exit GPF Back Performance Exhaust

Cobra Sport performance exhausts enhance the sound, looks and quality of your vehicle giving you the ultimate driving experience, while being fully guaranteed for assurance of our quality.

This BMW M135 (F70) performance exhaust is made with a combination of 3" (76.2mm) and 2.5" (63.5mm) pipework and fit from the Gasoline Particulate Filter section backwards (GPF-back). Offering improvement in terms of exhaust tone, bass and sound level, replacing the centre and rear sections whilst keeping the stock catalyst and GPF in place.

Featuring a single sleek look resonator to accentuate the factory valve functionality, transforming this ordinarily timid sounding M Sport model. With a selection of 4" (101.6mm) tailpipe options including a choice of carbon fibre tips.

Test Results:

Stock:
Sound - Engine at Idle: 60.8dB - Static 3,000rpm test: 73.3dB 
Weight - 21.7kg

Cobra Sport GPF-back Exhaust:
Sound - Engine at Idle: 73.4dB (+12.6dB) - Static 3,000rpm test: 94.2dB (+20.9dB)
Weight - 13.7kg (-8kg)

Please Note:

This 'Valved' exhaust retains the use of exhaust valves. On this model they operate dependent on throttle input, swapping from quieter to louder tones as before.

All relevant fittings and gaskets are supplied.

The Cobra Sport development team has been at it again and this time it’s all about refining the roar of the new BMW M135. With a few successful generations under its belt, the latest version of this premium hot hatch is here, and while the B48 engine might not shout performance straight from the factory, it certainly will after our engineers have worked their magic.

The updated BMW M135 sticks with the tried-and-tested formula: a 4WD platform, just over 300bhp, and the same 2.0-litre turbocharged heart. It may wear a refreshed face, but under the skin, it’s a continuation of the same formula that made previous M135i iterations such a hit. That said, the stock exhaust note leaves a little to be desired, the Cobra Sport team saw the potential and wasted no time unleashing it.

Designed to complement the M135’s premium feel, our valved GPF back direct fit exhaust system slots seamlessly into the factory layout, preserving your emissions compliance and enhancing the soundtrack.

Unlike some other value systems that respond to drive modes, the exhaust valves in this setup are controlled purely by throttle input. Go heavy on the right foot and the valves open, sending gases straight through the free-flowing pipework for an aggressive, sporty bark. Ease off the throttle and the system redirects flow through a resonator, keeping in-cabin noise in check and eliminating any chance of unwanted drone.

At the rear, we’ve made the most of the available space in the quad exit diffuser with a bold quad 4” (101.6mm) tailpipe setup. These tailpipes are available in a range of finishes including polished stainless steel, ceramic black, or the ever-popular carbon fibre.

During static revs, it’s immediately clear the system has a refined edge, but step on the gas raising the revs and the character changes. The valve response is instant, giving a punchy exhaust note under acceleration and keeping things calm when cruising. It’s the best of both worlds and it sounds as good as it looks.

Out on the road, the new exhaust really comes into its own. The throttle-controlled valves make every input feel connected, offering a subtle hum during everyday driving, and a sharp bark when you ask for more. It’s responsive, balanced, and genuinely addictive. As we like to say - performance you can hear.

Designed to elevate the driving experience while retaining everyday usability, the Cobra Sport GPF back performance exhaust is the perfect blend of sound, style, and performance.

BMW M135 (F70) Performance Exhaust Talk (Info, Sound, and Setup Overview)

Designed to demand attention, engineered to lead