No, supposedly they are functional diffusers. Try searching the forum a bit...there are TONS of threads about exhausts for the ISF.
On my car, the previous owner put a Borla system on it and it uses all four outlets and sounds great.i was curious if anyone has an aftermarket exhaust on their is-f. If so can you post pictures so i can see what it looks like? I am not exactly sure about the "fake" exhaust outlets. i am not trying to knock the F but is it purely cosmetic?