Unwanted reactions result in the formation of hydrogen sulfide and ammonia, which poison catalysts. Nickel or manganese is sometimes added to the washcoat to limit hydrogen-sulfide emissions.[citation needed] Sulfur-free or low-sulfur fuels eliminate or minimize problems with hydrogen sulfide. It also boasts the ultimate in customization, including the optional 700+ horsepower Shelby GT S/C version.

Installation was easy, and the craftsmanship and welds are very high quality. Mishimoto exhausts are constructed of large diameter mandrel-bent pipes for maximum flow. Mishimoto exhausts are perfectly engineered to provide an aggressively rich tone with no annoying highway drone. In general, though, you can expect to pay anywhere from $1000 upwards for a good cat back exhaust system. That may seem like a lot of money, but keep in mind that a cat back exhaust can provide a significant boost to your car’s performance and help it to stand out from the crowd. Typically a cat-back exhaust upgrade can be swapped with the original exhaust without any modifications.

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