Best addition ever was the installation of electric mirrors from a Chrysler Cross Fire. I installed them on the front lower corner of the window and good set them to have great rear and side vision viewing. I have since sold the car so can't show you pictures.
Best thing I ever did was add electric Chrysler Cross fire mirrors to the lower corner of the side windows. The rear and side vision was so improved I did not get nervous when driving in traffic for fear that I would miss seeing the surrounding traffic.
This is how the mirror bases were mounted on a Gelscoe car I spotted at Daytona HSR.
Thought I'd try a similar install on my car. Worked pretty well on the driver side, but mirror on the passenger side is positioned a bit too far forward to have a clear view, so I'll be fabbing a new bracket to move the mirror back a bit.