This will help aim smooth.
Disables DOF and motion blur while driving, use same line like for FC3 in GamerProfile.xml.
<Post>
<quality GameDepthOfField="0" CinematicDepthOfField="0" MotionBlur="0" id="ultrahigh" />
</Post>
in between </CustomQuality> and </RenderProfile>. Id should be same you have set in your game settings and after you save make it read only. Might not be necessary, but it wont hurt.