I've had my FLHP Carbon Fiber Lid for a few days now. First off, it's beautiful. The weave is in perfect condition and it has a gloss finish that is really eye catching. At the local cars and coffee, everybody comments on it.
Second, the sound is significant. I'm talking about, inside the car, over my loud exhaust, significant. If you're under 2500 RPM, it's quiet. Other than that, it's obvious you have a supercharger. You hear it right away. You don't need to rev the engine to see if you can hear it....you can hear it.
Also, the reason I bought it was to help fight heat soak. It doesn't get as hot and cools down faster than the aluminum stock LT4 lid. I drag race and haven't been to the track yet to see if it helps ET. But if it reduces heat soak, which reduces chances for knock, it's can't be bad.
AND it's almost 15 lbs lighter. Which is 15 lbs, high and in front of the center of gravity. That will help at the drags too.
For sure it's not cheap. But it makes more sense buying this one than spending $800- $1000 on one that's heavier, hotter, and not as AWESOME.