Most exhaust systems are also referred to as cat-back exhausts. This is because in general, aftermarket exhausts are made to start from the catalytic converter and go back. So in general BMW 4 Series exhausts include all the exhaust piping starting from the catalytic converter and going back, including the muffler and muffler tip(s).

Some manufacturers make axle-back exhausts, which do not include the segment of exhaust piping between the catalytic converter and the rear axle of the vehicle. Our product descriptions will denote if any BMW 4 Series exhaust system is an axle-back.

Many people buy exhaust systems so their car or truck will sound better. Lucky for us, many manufacturers do sound testing as part of the R&D process when engineering their exhaust systems. So there are a lot of good products on the market to choose from. If manufacturers make sound clips available for exhausts, we will have a link to it from the detail page of the product listing for the part. Otherwise, as a general rule of thumb, you get what you pay for when it comes to BMW 4 Series exhaust systems, meaning that the more affordable ones are an upgrade over your factory exhaust but probably won't sound as good or perform as well as the ones that cost more. The higher cost is normally attributed to large R&D expenditures in most cases, meaning you should expect better sound and air flow from the ones that cost more.

If you have any questions about exhaust systems we carry, contact us any time!

Q: What does an ehaust system do? Why buy an exhaust system?
A: A performance exhaust system is used to increase horsepower for your car by allowing exhaust gases to pass through your exhaust system with less backpressure and less resistance. Larger-diameter piping is normally used, depending on the application, in order to gain more horsepower and torque levels throughout the power band. A performance exhaust system can be the most cost-effective modification you can do to get more horsepower out of your car, not to mention that it will give your car a deeper more aggressive sound. And depending on the brand, performance exhaust systems normally include gorgeous new mufflers that add a great appearance to your car.

Q: How do you install an exhaust system?
A: Exhaust systems are installed using the supplied hardware, which includes gaskets and high grade bolts. This is truly a bolt-on procedure and most exhaust systems are an exact fit with no modifications needed. For this reason, getting a performance exhaust system is normally considered one of the easiest ways to gain noticeable horsepower for your car.

Q: What exactly does "cat-back" mean when people say "cat-back exhaust"?
A: Many performance exhaust systems are also referred to as cat-back exhausts. Cat-back means that the exhaust piping starts from your catalytic converter and runs back all the way to the exhaust tip(s).

Q: Does a cat-back exhaust come with a catalytic converter?
A: No, "cat-back" actually means from the rear of the catalytic converter back, so it will include everything after the converter, but not the converter itself.