I recently put on a top speed axle back exhaust for my g37x sedan, and was wondering how to make the sound deeper. Not sure whether to go with some sort of new pipes or an engine modification to get a deeper sound from the engine itself. I’m new to the car modification scene and would love some help.

 

Replacing the cats with either resonated high flow cats or non-resonated high flow cats will definitely give you a deeper tone. I can speak from experience there. Test pipes would also but depending on where you are, emissions may be an issue with the test pipes.