If you do go with HFCs using any part of the OE exhaust system will cause rasp and other noises you won't enjoy listening to.
Gary[/QUOTE]

You sure about that? Haven't heard on a g35 but have heard and rode in a g37 with Fast Intentions resonated HFC's. Zero drone or rasp .Not loud @ all either. In fact it was almost too quiet.

 

The g37 also has the vq37 motor. The exhaust not on those sounds different too.

 

I realize that the g37 has the vq37hr engine, but is the sound that much different? The 37 belongs to a friend of mine that lives in NY and we don't get together too often. I have heard his exhaust bone stock and with the addition of FI HFC's. Not much if @ all sound level increase.

 

I have driven the 08 z with the vq35hr, 04 z, my 05 g, and the g37. From what I heard was the 37 was a little quieter and not as ballzy in the low end. I didn't notice a lot of sound til 5k. My 05 g makes more noise at 3k.

 

I totally agree that the 37 is quieter than the 35.
Question is, if the 37 didn't really get louder with resonated HFC's, would the 35?

 

That is arguable because manufacturers will male each one different. I put resonators on my Silverado and I didn't know if it was running sometimes. From what I was told and knew it was supposed to make it louder. The only time it was louder was WOT. The 35 may be louder since the motor seems to make noise sooner and is quite a bit louder, but it would have to be tested to have a trua answer that isn't up to speculation.