Performance data for VVS aircraft?

[Korn]

Soviet aircraft had notoriously bad manufacturing standards, especially early in the war when they needed many machines fast. Much more so then any other country. So differences between a test plane and a real fighting plane could be huge, depending on batch and even on an individual basis.

Also the commie propaganda machines would make sure to crank up to numbers for "morale".

Sorry for my poor english, i'm in a hurry.