Another couple options:
1. mudflaps that extend back to the rear
2. clear protective applique (aka "clear-bra" or "helicopter tape").
The rubber is one thing; from years of burnouts, the lower quarters on my Duster are peppered with stone chips.
For my '64, I made some mudflaps that have a horizontal extension that runs back to the rear. 3 quick fasteners attach them. Required drilling 3 small holes each, not really visible but unfortunately necessary.