i can back up everything you have said so far about the nismo exhaust being a nismo owner, it is quieter than a stock G37 exhaust but it is like an aftermarket exhaust in the same sense that its true dual and flows well

i think the nismo 370z exhaust could be made into a good exhaust, 2.5in H-pipe(so it matches the mid-pipe), and top speed/aam/custom axle backs but that wouldnt be worth the money imo

a custom H-pipe would cost at least $250 and axle backs will cost at least $100 assuming you find an exhaust shop that will do it for that cheap, so you would be looking at $850 max for a nismo exhaust and modifying it and for that kind of money, you can get a top speed exhaust which is true dual with an X-pipe and it will have titanium burnt tips and save $200 on top of that

While the OEM nismo exhaust is a quiet exhaust, it's definitely different then the oem 370z exhaust. It's much deeper. You guys are right if you sit inside your car you can barely tell the difference between the nismo and oem exhaust. But I've heard so many times when people drove away my car. It's noticeable deeper and I was surprised it sounds pretty mean at low rpm. Matter of fact many random guys on the street complimented on my oem nismo exhaust. But it's not very impressive at WOT which is why I got my HKS and very happy with it.

What you are hearing is the pipes themselves vibrating.

The exhaust has more pipe and longer straight runs, this makes for a lower resonate frequency as compared to the stock Y Pipe setup.

You can hear it inside the car because the vibrations are transmitted into the chassis because of how close in proximity the exhaust is and people can hear it when you are right next to them, but that is it.

I've explained this before in another thread, basically it isn't sound being emitted by the exhaust gasses making the sound, it's just the organ pipes under the car vibrating.

So yeah, the car will sound different on the inside, and if you are pulling away from someone who is real close to you, they'll be able to hear it for the first ~20 feet or so, but after that, you're silent as a ghost. It's also just a deep drone, it isn't a real "exhausty" sound.

Go with a new Beluga exhaust for under 399.oo... A few of us have it and its true they'll say it's a great bang for your buck. Stainless steel and tig welded...just my 2 cents.

You are probably right about the lower resonate frequency thing. And I do agree it's a quiet exhaust compare to all other aftermarket exhaust systems. But still, if you want to save up some money. The oem nismo exhaust is a good choice. It sounds not THAT bad after all.

Very old post but wondering if you got the NISMO cat-back exhaust after all and if you liked it... :icon14:

I recently put the Nismo system on my z,everyone says it’s too quiet and they are right,not much louder,just a little deeper sounding.Performance wise the H and mid pipe are supposed to be pretty good.I ended up getting the AAM axle back muffler to give it a little more growl.Overall I am happy with the sound now,still considered quite quiet,but with just enough grunt for my old ears.