There are loads of options, all offering different benefits, and the amount of research you do can quickly turn to frustration when you realise the minuscule differences between the many options. OE-quality exhaust products engineered for today's medium-duty and heavy-duty vehicles. The single 60mm is split into twin 50mm pipes to the twin silencers.
The only difference is that it features 335d straight pipe perforated pipes. The original exhaust systems focus more on just reducing the sound and not shaping it to give it that desired deep growl. One function shared with both the axle-back and the cat-back exhaust systems are shaping your vehicle’s tone.
By running pipes from the catalytic converter to the muffler and from the muffler to the exhaust tip, cat back exhaust systems improve exhaust gas flow, providing small performance boosts. However, your performance gains may be limited if your catalytic converter restricts gas flow, as a catback exhaust system is installed ‘downstream’ of the converter. Header-back systems are increasingly rare, namely because of modern emissions systems. Since removing your vehicle’s factory emissions components is highly illegal, the previous two options are more common. However, header-back systems are still available for some older, pre-emissions applications. In these cases, header-back systems offer more performance and volume than cat-back or axle-back systems