First of all the package was shipped really fast. It came with everything you need for the install. (not tools) Once the stock header and exhaust were off the new header and cat-back slipped in with no difficulties. Lined up perfect all the way through the rear bumper. It sounds awesome. It doesn't sound ricey but actually has some bass in the exhasut. The muffler is Magnaflow. As Far as horsepower it was probably good from about 9-15 hp by itselves. I do not know exactly how much it added since I didn't dyno the car after install. I defently recommend to anyone.