 When you're modifying the exhaust on a turbocharged car, the exhaust as a whole can be broken down into a few sections. We start in the back of the car. You've got exhaust tips, usually mufflers. These parts are usually found after the rear axles up here. Sometimes you can change just this part. You would call that an axle-back exhaust. Now we move forward. There's usually a long pipe or maybe two. This one has a resonator in it. You'll follow it until you find the catalytic converter. In this case, it's stuffed way up inside of here. But from this flange all the way to the back of the car, including the axle-back, would be called a cat-back. The next pipe goes up into the engine bay and bolts to the turbo. This section houses a catalytic converter and your rear O2 sensor because it comes down from the turbo and connects to the rest of the exhaust. We call just this part the down pipe. When it's connected to the cat-back and the axle-back, the entire thing is called a turbo-back exhaust. From car to car, the exact configuration is going to vary, but understanding the terminology for each part is going to help a ton when you're shopping for parts and trying to use the right tune.