[jrg]

Generally the combination of rpm and mp are indicated in the plane's handbook and low rpm with high manifold presssure should be avoided because of the detonation problem (I've made some posts in this thread before about CEM where i speak about MP, RPM and prop pitch systems). For a lower MP than full power you should normally use a lower rpm than max rpm (again as the handbook indicate).

The airbrake effect you are speaking about is right, but normally as long as you keep MP and RPM in the right range/settings there shouldn't be any problem because the thrust to drag ratio is optimised when using the rights settings.

The shakings are not constant for me but there is a kind of stutter every 10 or 15s, I don't think this is related to graphic problems but only to a (maybe flawed) behaviour of the plane, because when I'm in external view or in cockpit view but without CEM or headshake activated the problem dosen't appear. For the vibration I still can't tell if it's a normal reaction of the plane due to a resonance effect induced by a certain frequency or an overmodelling/flaw.