Pentagon i'm not saying you didn't have any gain! If the story about the stock catback being 50mm is true it's normal that you feel the car faster (the sound has always a bit of effect), and the K%N of course does it works (where does it takes the fresh air, same pipe of the stock one?)
The 99 ron fuel helps too, the new ecu has a wider range of self-adjustment than the previous car.
I see you tried with different cars, did you drive alongside and try acceleration in the same gear? It's one of the best way to see how fast is a cas, overtaking is deceptive.
Could you simply take a stopwatch and measure the 30-70 mph time? So another R56 owner can do the same!
Did you notice a gain in top speed? It's one of the figure that reflects better a gain in hp. I guess a ~200 bhp r56 should hit a good 5 km/h more than a stock one, of course measured with a gps. Often the direct air intakes have problem at high speed that the rolling road doesn't simulate.
So i guess you can tell me, why did you use different correction factors? What were the air temperature and pressure? Does the rolling road have good ventilation, is it a brake or an inertial system?
The 10 bhp increase at the wheels is just with and without the apollo intake or stock and then quicksilver+apollo?