Performance Downpipe

All welds are held to strict quality control standards, and the pipe is made from 16-gauge metal. This downpipe is designed to eliminate the flow restrictions found in the stock exhaust, such as double-walled tubing, a restrictive catalytic converter, and the infamous "U-Bend" section that is crushed by GM to accommodate a rear O2 sensor. By replacing these components, the ZZP downpipe allows for improved exhaust gas flow, which can result in gains of over 15 HP, a substantial drop in knock, and the potential to drop a pulley size or eliminate knock by 5-7 degrees. Users may also experience more "pep" in the low end and more pull in the top end. This downpipe includes a high-flow catalytic converter that is EPA certified, though it does not meet CARB compliance. It utilizes interlock flex, which is considered the best option for boosted applications as it withstands higher temperatures and provides a smooth surface for exhaust gases, unlike single-wall flex pipes that can cause whistling or ticking noises. ZZPerformance offers a choice of 2.5-inch, 3-inch with a 3-inch exit, or 3-inch with a 2.5-inch exit. Installation is typically achievable in under an hour. It will only fit the 3800 V6 engine and does not fit LS4 V8 cars. It is compatible with the following vehicles: 1997-08 Pontiac Grand Prix (Series II, Supercharged and Non-Supercharged), 2000-05 Monte Carlo (3.8L Engine Only), 2000-05 Impala (3800 3.8L Engine Only), 1997-04 Regal (3800 3.8L Engine Only), and 1998-99 Intrigue (3800 3.8L Engine Only). For 2004+ Grand Prix (Series III cars), a style "B" O2 extension harness is required for the rear O2 sensor, and for the 2008 Grand Prix, a style "C" O2 extension harness is needed. Gaskets for the exhaust manifold to downpipe inlet and for the downpipe to factory catback/2.5" catback are available separately. ZZPerformance also offers store credit for customers who wish to sell their stock catalytic converter back.