SLPs Mustang Loud Mouth has always been the best performing cat-back exhaust in the business. Now its the most versatile, too. Using groundbreaking modular technology first seen on our Mustang X-pipes, weve developed a system that can be quickly reconfigured to fit changing performance, noise level, and sound quality requirements. Simply loosen a few band clamps, swap muffler types, re-tighten, and youre done. No other system offers this level of performance and adaptability.