Texture resolution is always dependent on your setting.
Check you are using the maximum global texture size, and that you are using anisotropic filtering on your video card control panel, at least at 8x.
The animated ground vehicles responds to the Scenery Complexity setting (not the vehicle complexity setting), and you might want to turn down the vehicle density, to get rid of the default ones, which are less fps friendly then the one that come with the scenery.