My buddy has a crossfire. He had a custom exhaust put in. It has a x pipe put in after the rear cats with dual pipes to the back with no muffler. His sounds like hell because it's an auto and it drones but on a manual it would be sweet. What does an X pipe do for an exhaust? also people tell me I will hurt my engine with a high flow exhaust because of the reduced back pressure. But i call bs. This car has 4 cats. I believe that is plenty of backpressure. What's better? True dual (with and X pipe or no X pipe) or keeping the stock design with bigger piping?