Regarding Luftwaffe kill confirmation - can't cite anything ATM, as it's been long since I've read anything on WWII planes. But if you read the last interview with Erich Hartman, he mentions, that his score was questioned at some point in the war (if confirmation was rigorous, why would anyone question and on what grounds?), so they sent a guy with him to report on his combat flying and he confirmed that Hartman actually was THAT good (again why would they need to do that if confirmation was rigorous?). On another occasion, Hartman mentions that he went behind three IL-2s and shot one in the radiator, the Russians panicked and the whole flight crashed into one another - Hartman states that this counted as 3 kills (though he actually only fired at one, which is what he would get by RAF standards).
Anyway, this is not the issue here. I agree that the 190 was a great plane and manoeuvrable at high speeds (450TAS as mentioned seems legit), the thing is, now it's quite manoeuvrable even at 300km/h at 1000m and just seems a bit odd. Not to mention it won't slow down.
