Dear DT I have found two bugs.
1. Cockpit in Yak-3P should be moved backward as it is in Yak-3 VK-107 (all blueprints of Yak-3P have this position of cockpit).
2. (the most important for me
) The wings of Yak-3 VK-107
They should have the same shape and area as Yak-3 wings not Yak-9U!!! It is not a very difficult operation to replace the correct wings from Yak-3 3d model I guess?? The other thing is wrong armament of Yak-3 VK-107 it shoult consist of two B-20 canons.
Why J2M3 maximum speed is 640 km/h at altitude 5000m and J2M5 696 km/h at altitude 9200m? All known data of this types show maximum speed 586-612km/h at altitude 5000m. I'm not sure about J2M5 because it has additional supercharger stage.
I've tested those speeds in Crimea map with 25% of fuel and without ammo.