In my opinion its never annoying because its only for a certain RPM on decel

 

It's subjective. What might be annoying for one person isn't even noticed by another.
It's most noticeable for me on deceleration esp when I decide to pop it into neutral and coast to a stop.
The hiss will be slightly diff with diff exhaust setups too.
Your best bet is to ride in a G that has HFCs.

If I had to do it again I'd still get HFCs.

 

^ thanks guys appreciate the input, im a bit wary about the sound which is why i havent yet gotten the HFC but now that im looking into getting a tune the shop told me that HFC would yield much better results. i am trying to find someone who has HFC on the G sedan in the area. thanks for the input though!

 

Everything about the sound is better with the HFC's. The performance is probably negligible in real-life driving, so the sound is the biggest gain in getting them. If you're getting a tune I would DEFINITELY get them installed first though...

 

good to know.. I have a stock car now, and was going to get a tune, but I figured I'd gain more with some kind of mod - it seems like HFCs are the best thing to do first, then cat back exhaust?

 

I got FI HFCs and the only time I hear the hiss noise is from 5K to 5500. Not terribly annoying but it is there. I was expecting the car to be louder after install but they did get a little louder after a few weeks. I am very happy with mine and would do it again. I would recommend getting all new oem gaskets especially between the header and cat so it will save you headaches down the road.

 

Yeah, oem cats are the most restrictive part of the exhaust.
HFCs are def a great place to start.

 

I thought if i got new FI HFC from FI themselves then it would come with the gaskets, no? Seems like a cheap move to not include $15 gaskets with a ~>$350 order.... anyways where to get them if they dont include them??

 

stealership?

 

It only comes with the ypipe to cat gasket. You must reuse the header to cat gasket or buy a new one. All the after market dealers do this its not just FI. I got them from Infiniti dealer $55 for all 4 gaskets that price is BS but I havent had any problems so far.

 

^ wow that price is a rip off, so basically i would need 2 baskets from headers to cats, should be able to get these online for ~$20, thanks for the input guys.

 

I just drove around today after the FI HFC install. What a difference! I also installed two new O2 sensors for safe measures. Performance was smoother with a noticeable deeper sound. At WOT, I felt a difference from the Mid to the Upper Range band of the RPM's. It was fun especially at the 70 to 90 MPH range. No complaints here.

 

On my order, FI gave me gaskets for the front and rear, along with the bolts and a free Got Exhaust License Plate.

 

^ thats what im talking about! did u get them straight from FI and how much were they and did u get metallic as well? thanks!

 

Yes I did get them from FI. They were 500. They appeared to be white, so I would think that they were metallic with a ceramic coating.