When it comes to exhaust on your Mustang, it’s all about sound. Unless you’re going with a long-tube system on a supercharged Two-Valve, you probably won’t pick up much power. That was the case with our Bullitt. James also tuned our Bullitt on Brothers’ Dynojet, and it was an eye-opening experience. We gained the trademark Mustang sound we were looking for, any horsepower gain would just be a bonus. Turns out, we didn’t really gain peak horsepower. However, we gained midrange horsepower and torque, as much as 9 hp and 12 lb-ft of torque.