Sorry Demetrious but you need to read some more then.
Erwin Leykauf, German fighter pilot, 33 victories.
"During what was later called the 'Battle of Britain', we flew the Messerschmitt Bf109E. The essential difference from the Spitfire Mark I flown at that time by the RAF was that the Spitfire was less manoeuvrable in the rolling plane. With its shorter wings (2 metres less wingspan) and its square-tipped wings, the Bf 109 was more manoeuvrable and slightly faster. (It is of interest that the English later on clipped the wings of the Spitfire.)
For us, the more experienced pilots, real manoeuvring only started when the slats were out. For this reason it is possible to find pilots from that period (1940) who will tell you that the Spitfire turned better than the Bf 109. That is not true. I myself had many dogfights with Spitfires and I could always out-turn them. This is how I shot down six of them."
Walter Wolfrum, German fighter ace. 137 victories.
"Unexperienced pilots hesitated to turn tight, bacause the plane shook violently when the slats deployed. I realised, though, that because of the slats the plane's stalling characteristics were much better than in comparable Allied planes that I got to fly. Even though you may doubt it, I knew the Bf109 could manouver better in turnfight than LaGG, Yak or even Spitfire."
Herbert Kaiser, German fighter ace. 68 victories.
"Personally, I met RAF over Dunkirk. During this battle not a single Spitfire or Hurricane turned tighter than my plane. I found that the Bf 109 E was faster, possessed a higher rate of climb, but was somewhat less manouverable than the RAF fighters. Nevertheless, during the campaign, no Spitfire or Hurricane ever turned inside my plane, and after the war the RAF admitted the loss of 450 Hurricanes and Spitfires during the Battle of France." In the desert there were only a few Spitfires, and we were afraid of those because of their reputation from the Battle of Britain. But after we shot a couple of them down, our confusion was gone."
Pierre Clostermann, Spitfire pilot.
"I tried to fire on a '109' that I spotted in the chaos. Not possible, I couldn't get the correct angle. My plane juddered on the edge of a stall. It was comforting that the Spitfire turned better than the '109'! Certainly at high speed - but not at low speed."
Skip Holm interview about P-51 vs Bf-109 vs Spitfire:
View: https://www.youtube.com/watch?v=TFl8X4y9-94
Mark Hanna interview on Bf-109:
Flying the Bf 109: Two experts give their reports | Flight Journal | Find Articles at BNET
And there is plenty more where that came from!
As for estimating a/c performance, sorry but we disagree, there's nothing magical out there that can't be explained. But if you wish to place all your faith in 60 year old data and disregard both physics modern day assessments alike then be my guest, but I don't have to be like that myself.