I have one. You will notice that the engine will rev and accelerate quicker, but it's nothing drastic. I've found that it helps mostly when coming off the line and in between shifts because it doesn't shock the rear tires as much, resulting in better traction. I doubt it'll free up more than 2-3 HP on the dyno though...if that.
sl03gt said:
My 1/4 mile times won't really mean much since the before and after runs weren't on the same day, but...
before: 13.489 @ 102.96
after: 13.212 @ 103.15
I could feel a difference in the way the car pulled after the aluminum FW was installed, but it wasn't a night and day difference. It just felt smoother and a little more responsive than before.