The exhaust manifold found in the 2007-2012 Jeep Wrangler, Cherokee and Grand Cherokee was designed to combine the exhaust gasses from each of the 6 cylinders quickly with a manifold that was cost effective to produce. Our shorty style off-road header is a 3-1 design to allow the exhaust gasses to flow more freely from each of the 6 cylinders and combine in a more efficient manner. Tubing has been optimized for the 3.8L engine. This creates a reduction in cylinder backpressure and improved exhaust gas velocity. These improvements free up lost horsepower and torque. An added benefit is a more performance oriented exhaust sound.