Hi all,
I have with me (in combination with the STILLEN supercharger) installed the following version:
F.I. TDX with 18 "resonator
F.I. HFC with resonator
Without the HFC no dron in the inside. Outdoor deep and loud. A sensational sound!
With the HFC is a dron in the inside at 2'000 r / min. Outdoor deep and
very loud!
My neighbors are in the kitchen the dishes out of the closet! 
With a standardized measurement, we measured 108 decibels at idle speed 900 r / min!
I must say that the supercharger kit increases the volume a bit!
Enclosed is a film (from minute 2) where you can hear the whole thing.
F.I. TDX 18 "resonator and F.I. HFC with resonator
Nissan 370Z STILLEN Supercharger & F.I. CBE 18" - YouTube
Hope to have helped so?
Greetings from Switzerland
Ivo