I have been looking to see if my 260z has factory mirrors or aftermarket parts and unfortunately is not original so great thread to find.
My ta22 celica has similar design mirrors that are designed with a slight (although more noticeable than the zed ) angle to be non interchangeable each side.
So now that i know i need a pair of new mirrors for my 260z is there anywhere in particular to find either side or are these becoming rocking horse poo items ?