I have requested this before but I think it needs to be brought up again. We need to have some sort of engine idle sound when the engine is at a certain RPM. At the moment it sounds rather unrealistic and frankly bad no mater what sound pack you're using. ARMA II handles this really well I think where when the engine starts to get over the RPM threshold for idle the idle sound file and engine running sound file with the pitch changing are slowly mixed together and the idle is sound file is slowly speed up until it transitions to the engine running sound.