Aah, lovely - I somehow overlooked it!
As far as I can see, the average power increase (looking @ STUs PDF pics from the thread he linked to) seems around 4 hp and the maximum power increase around 10 hp. Now, even if the readings are incorrect, the relations of the measurements aren't (as long as both measurements are made at the same time, one after another).
But what surprises me the most, is that hole @ 5500 RPM, being nicely "patched" with the GSR kit on. I never saw anyone mentioning the problem in the threads before but boy it did bug me! The attachement also shows that going past 6000 RPM makes no sense, which probably many of us realised while driving.
I would love to hear the sound it! Heres how it sounds stock:
BTW - do GSR makes the filters themselves?
F