One proven way to free up lost horsepower is by replacing the restrictive stock catalytic converter with a free flowing test pipe. The MXP G37/370Z test pipes feature 60mm piping for optimal flow without sacrificing backpressure and are offered in both resonated and non resonated versions. All MXP performance products come with a 3 year limited warranty from the original date of purchase. Please note that this product is intended for off road use only!