I drove in a new G37 yesterday. The Tanabe sounds has a deeper tone and is a more noticable (loudness) than the G37. I'd say that the G37 needs an aftermarket exhaust as well. The G37 stock exhaust is tame and not like that of the early G35s where you could actually hear it.

The Tanabe installed on my IS has no drone at any speed. I know all about drone and I am very sensitive to it. In the cabin, the Tanabe is perhaps the nicest sounding exhaust that I've heard in some time.

 

I have driven my friends 350Z and it does not sound anything like my Tanabe. Tanabe is lower in tone, not too loud and perfect for the IS350. Also, I have no droning issues. Tanabe as well, in my opinion, has the best looking tips out there for the IS.

 

I posted a video of my 2006 IS 350 with the Tanabe Medallion Exhaust. The first part of the video is the sound inside the car and the second part of the video was taken with the camera attached to the rear of the car.

http://www.youtube.com/watch?v=3VrnduuzgxQ