Hi Tom, I also recently ordered a carpet set for my 1971 Chrysler 300 2 door and after looking at all the offerings I also chose Stock Interiors just as
@Big_John did. In my case I also included the mass backing for sound deadening and I like how well it is molded into the back of the carpeting. Stock Interiors also has the correct heel pad for our cars. I looked at all the other offerings and Stock Interiors was the best in my opinion. I will be installing mine soon once the car comes back from the body shop where mine will be painted in its original April Green Metallic (GJ4) color.
Your 1971 Chrysler 300 FQ5 Coral Turquoise metallic paint is also one of my favorite colors.
Before you bought the car I had talked with its previous owner and he told me he put urethane bushings on his strut rod ends - if that is indeed correct then that alone makes for an unbearable harsh noise even going over mild bumps that obliterates any hope of a quiet ride. I made that mistake once and I couldn't wait to get them changed to the standard bushings.
Best wishes.
Steve