Very very few planes in WW2 used a nitrous system (GM-1 for the germans is the only one I can think of, suitable only above 30,000 feet or so).
All other additives are cooling agents to lower temperatures (yes, LOWER them!) so more compression could be made without premature detonation. On top of that, MANY "war emergency power" settings require no additives, they simply increase the RPM and MAP beyond a certain limited point.
So, no... Simply running an engine for 5 minutes on a WEP setting will never, in any case, destroy the engine like most other sims pretend. It's as artificial as any other decision in a computer game.
As for your cockpits argument: Nobody in TW uses the instruments, they all use debug console for every bit of info. I doubt they ever look at the cockpit except for the gunsight. In IL2 nobody uses the cockpit, either! They either turn it off to get the nice handy ctrl-f1 view, or they use the speed bar for heading, alt, and speed. Why? Because they have stupidly designed layouts that don't give you any of the info you need. [EDIT: As mentioned in real life it may work, but on a computer screen it's retarded] Hell, IL2 even brags that their new BOB game is going to have "realistic" compasses that swing back and forth 90 degrees never telling you what course you're really on.
Riiiiiight.
Because in WW2 they really flew north when they were trying to go east every time, right?