> Check your owners manual.  Does it say you can drive the car without the
> mirror?  This is akin to removable seats and roof racks.  If the owner's
> manual says you can remove it and drive it that way on the road, then you
> can drive it that way in an autocross.
> 
> If you can't come up with paper from the manufacturer telling you how to
> remove the mirror and drive the car without it, then you must leave it on.
        ---
        If the owners manual states that you should observe all local DOT
regulations, and following THAT if you have two side mirrors, you are not
required to have a windscreen rear-view mirror (in most states).
        Leap of faith, but tangible.
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