I've taken the data provided by the devs and put it in a table for a plausibility check. I've been calculating the overall efficiency of the aircraft in the sustained level turn at sea level.
Several odd things pop up:
The B109F-2 is clearly worse than all other Bf109's, even worse than the Bf109E-7. That's odd.
The LaGG-3 and both Yak-1's are miles ahead of the competition.
The I-16 performs very poorly, even for a design as chubby as it is.
The Ju87 perf