between stillen and F.I with 18" res

Tresfr

I have only heard Stillen and F1

The order of those from loudest to quitest at cruising speed as well as a few others from what I have gathered is shown below. It also depends on what speed and RPM because even the F1 at some Highway Speed was very quite but the Stillen seemed to be quite at all cruising RPM. The only one that may be like stock which is nearly silent at cruising speed is the Nismo CBE.

I immediately liked the Stillen because I was looking for the same characteristics as you. Ultimately I choose the Invidia because it has much better build quality and fitment and is a little lighter than the Stillen. It appears from reviews and clips as well as a few responses from owners I spoke with to have a slightly mellower tone. ( I will be getting the Invidia Installed next week)

F1 is the class of this field as far as weight, power and build quality but you must live with some drone at certain throttle input and RPM ranges. It has the deepest tone of this group and that is what some people like while others do not.

Cruising Speed 70-80MPH
F1= 10
Stillen= 7
Invidia= 6
Nismo= 2
Stock= 1

Horsepower
F1= 21
Stillen= 18
Invidia= 12
Nismo= 5.8
Stock= 0

Wide Open Throttle
F1= 10
Stillen= 9
Invidia=7
Nismo= 4
Stock= 2

I know my opinion based on what I heard will not be what others may feel because how one person perceives sound can be different than another. If there is anyone who has heard in person 3 or more of these CBE only who disagrees with my thoughts please chime in. I would not even try to get into how they sound with High Flow Cats because the comparison becomes far to complex.