Objectives behind the design of the 370Z/G37 Resonated Test Pipes are simple; increase exhaust flow and enhance exhaust note, while minimizing drone and rasp. It is not uncommon to develop drone and rasp while freeing up the exhaust flow of your vehicle. Although the Resonated Test Pipes will not guarantee a complete drone/rasp free set up, we can assure you that the additional resonators in the test pipes will combat odd exhaust frequencies that contribute to drone/rasp. The factory catalytic converters leave a lot of power on the table with their smaller piping and extremely dense core. While being a very simple and inexpensive bolt-on modification, upgrading to aftermarket test pipes is a no-brainer. Resonated Test Pipes replace the factory catalytic converters and are designed purely for off-road performance.