Which style carpet and how does it compare between suppliers?

The ACC stuff is good quality. It holds up well under everyday usage. It's not too difficult to install, just have to take time and be systematic.

When you ask the question best, I have to ask what kind of car is it and what are your goals? The 72 and earlier cars used a 100% Nylon loop pile carpet. The books I have say 72 and later use cut pile. I've seen a few of each in the 72 and have seen loop pile in later 4-doors. IMO loop pile wears better than cut pile.

Why the 80/20? It's cheaper to make and less likely to turn you into a static electricity generator. If you've experienced a spark jump from your hand to the dashboard, you know what I'm talking about.

The heel pad changed in 1967. Many merchandisers will try to sell you the ribbed pad instead of the dotted pad for a 1966 car. It's wrong. The '66 Darts used the dotted heel pad. (Rule of thumb match heel pad to the brake pedal.)