The engine uses a maximum of 3 shadows. This offsets all model levels of detail by the given amount. This should be used for a 'low detail' setting for slower machines. This defaults to 150, which saves 300 triangles for shadows. Anything between 0 and FarDetailDist has its detail level scaled in between there.
Higher numbers print out more information.
Offset the mipmap level that it uses by a certain amount. This helps on crappy cards with very little texture memory. Turn on or off particle drawing. Turn on or off sprite drawing. Turn on or off model drawing.