I know they are major $$$$, but I'm really particular about sound and I've heard that the Nismo's are quiet. I already have Nismo headers and cat-back and really don't want to go any louder.

 

hf cast = louder.

 

I haven't hear them but from what I read they are slightly louder than stock but not nearly as loud as HFC's or Test Pipes. Also you may gain a few HP's from them. Probably about half of what HFC's produce. I was tempted to get them myself but I already have RT HFC's (which with Nismo headers and catback is pretty damn loud).