What is concerning is the response received: “The engine model contradicts the P.I.1A-MB326K-1 Flight Manual MB-326K. However, it is accepted as a suggestion due to the sufficient number of sources. Thanks for the report.”
Relevant information on this matter has already been provided (attached extract).
However, I believe it is important to clarify that the manual P.I.1A-MB326K-1 refers to the MB.326KC, which was the version exported to South Africa (AKA the Atlas Impala).
As that country was under embargo, it could not receive the updated engine. Therefore, this seems to be incontrovertible proof of an incorrect implementation that should be corrected as soon as possible.
The model featured in the game is the 326 K – RS-25 mm, registration MM54391, construction number (C/N or MSN) 6478/219, powered by a Viper 632 engine.
The manual for this specific aircraft is not publicly available, and secondary sources have already been provided. However, manuals for the KD (Dubai) and KT (Tunisia) variants can be found online and purchased for a small fee if needed.
PS the name of the manual in the answer isn’t even correct as far as I understand, missing “C” letter, so our sources don’t really contradict with anything, since the manual is for another variant.
If you have manual, maybe provide it to @Smin1080p_WT via PM, as I understand the actual problem is similar to Re.2005 VDM, they lack data, like performance tables/graphics to make flight model with correct engine.
At least I think it would be the best way, I’m sure Smin can help us to attach this manual to existing bug report and provide information to devs.