I have to say that the tests on the Spitfires are fairly consistent, though the tests on the Bf 109's are not; mainly the G's.
It seems as though the RAF pilots and tests state that the 109's turning is very inferior to even that of a P-51B or even D mustang. The Germans state otherwise.
I believe the speed figures seem accurate though.
There's a LOT of good data considering Allied aircraft though, here:
http://www.wwiiaircraftperformance.org/
It really does look like the best resource I've ever found online concerning the performance of mainly British and US aircraft types.
Let me tell you, the figures are very very different from BoP values. But I think I'll be happy if at least the Spitfire XVI's roll rate was fixed.
EDIT: Btw, Wildar, did you show these figures and charts to the devs, or at least post it in the 'Suggestion to Devs' thread? I think if you got a nice, wide JPEG displayed in there, it would catch their attention.
