Before everyone gets all gungho about why didn't I use the "search" button and watch sound clips on YouTube. Trust me... I have. For the last two months i've been researching on threads from 15 years ago, as well as sound clips. It is difficult to find info that is from 2019 or 2018 with some searches leading me into the sedan sections. Also when I do find some good information many posts seem to have a surplus of other mods attached to the vehicle that further increase the sound of the exhaust.

I would like an exhaust that would just bolt on cat-back or axle-back that would just sound a little louder, deeper, than the OEM exhaust, for a 2004 G35 Coupe. That is it, no high flow cats, no deletes etc.

From what I concluded the best to be able to achieve this result is the

Invidia Gemini cat-back with the rolled titanium tips (HS03IG3GID) or...

NISMO S-Tune cat-back (B0100-350SM) which is actually for the 350z but will fit the G35

so are these the best options, is there a better option? which one out of these two would you take?

 

I have the Nismo NON S-tune with a Tanabe Y-pipe and FI RHFC. Loud when revved high, but barely droney around town/little bit of drone highway under load. With stock cats (and probably even with an aftermartket y-pipe or an HR y -pipe), I imagine it would fill the expectation you're looking for.

HFC seem to be the single largest sound increaser from my experience, although HFC and stock exhaust sound like OEM+ with no drone. Keep in mind with the Nismo exhaust that you'll need to extend the tips or else they're tucked into the bumper.

 

I put an HKS cat back on my Sedan 14 years ago and it's still perfect.

 

I have the invidia Gemini on my g35. I got the invidia HFC as well so I’m sure my exhaust is louder than just the CBE. It still sounds amazing I just get a bit too much drone with all the windows up on the highway. As soon as I crack a window though it improves significantly. If comfort is important to you I would go with the Nismo.

 

I've done a simple mod to my totally stock exhaust system just to give it a bit more loudness and rumble. People say it sounds like I have a nismo exhaust.

 

i have greddy spectrum elite, its an axle back set up, a bit louder and feels flow better than stock 4 sure

 

what you end up doing?

 

Both those exhausts you listed will drone, I recommend the Fast Intentions resonated HFC and keep the stock coupe exhaust. Still sounds the same it's just a little louder, no drone, no rasp. Plus you get rid of the highly restrictive factory cats.

 

Interesting. Same case on autos?

 

Speaking of cats, do I need to retune my g for my hfc’s? I remember reading somewhere that the engine will be running lean until I do but I thought the ecu would self correct that.

 

You will want to retune. That's a pretty major change.

 

Good point, not totally sure about autos.