One main reason for choosing to remain with a stock system is because it comes already installed on your vehicle. You should know the difference between a dual exhaust and a dual exit exhaust system. But it is easy to mistake a dual exit exhaust for a dual exhaust system. The materials are often 304 stainless steel or aluminized steel. The stainless steel is usually coated in special metals that make it corrosion-resistant. This means there will be a reduction in the amount of load on the engine, leading to higher mpg and fuel efficiency.
The cat back system’s pipes have a larger diameter than a standard set. So, your vehicle will get to perform better at a fraction of the work it outputs. An 
