Hi Thefin, welcome to the forum
The flight models of the planes (sim mode) came straight from maddox games' original Il-2 PC title, apart from that, BoP is a completely different software. Most people believe there was some 'lost in translation' though. All aircraft in BoP climb waaay better than they were realisticly able to, then there is the infamous Mustang with incredably high drag and terrible stall characteristics.
You also have to take into acount that in BoP many aircraft management things are done automaticly, simplified, or completely deleted. In real life, proper use these things like RPM setting/prop pitch, fuel mix, supercharger stage, would be what would get you the high speeds and altitude.