What it should have said was "our HFCs don't amplify the hiss." We've done a bunch of testing with our different exhaust systems and should have videos today of a couple of them.
Here's a video of our HFCs paired with a Fast Intentions CBE on a G35
https://www.youtube.com/watch?v=AlRacQGX4io
Here's a video of Fast Intention HFCs paired with their CBE on a 370Z
https://www.youtube.com/watch?v=IuAkiRHSmDY
And a video of our HFCs with our 2.5" TDE on a 370Z
https://www.youtube.com/watch?v=40wAvCXEItc
As you can tell the cars with our HFCs do not have that same level of "hiss". The type of catback the car has can also help, but I can't find any videos of cars with just the HFCs.