1) "The FIA inspects all engines" What does this mean exactly? Do we have any in info on when and where the FIA has inspected any engines?
I doubt any race engine could be inspected before the team has decided that it wants to rebuild it.
2) Engine variations: The engine manufactures have been in business for a long time. They have very good statistical data on what output variations they are going to see. The teams are told what to expect for the year. The teams can verify output numbers on their own to verify the builders data. This is a business arrangement with negotiated requirements.
3) I would expect any engine that is out of the statistic norm to be torn down and examined to see what is different with the particular engine.
Brian