Catback
The Cat-back exhaust system has a larger diameter piping compared to the stock and axle-back exhaust systems
Its tubing is also higher-grade mandrel bent. These two work together to offer better flow and allow the system to breathe better.
Note that, while large-diameter tubing is an advantage, it can also be a disadvantage if overdone.
Extremely large-diameter tubings result in a pile-up of exhaust gases and slow exit.
This can lead to a significant decrease in torque and horsepower as well as rpm.
But if you are making your order on partcatalog.com, you can always inquire about the recommended tube diameter for your exhaust system by providing your make and model.