I'm no metal worker by any means, but I've had some recent experience replacing floors in my Challenger. Due to pricing I got an AMD complete front floor pan and Goodmark individual rear floor pans. The only issue I had with the AMD part was a shipping issue. The complete floor is so big that during shipping someone dropped it and one corner had a tweak. A little time with some hammers and pliers got it back in shape and it dropped right in. The stamping is so good that my U.S. Car Tool frame connectors fit right up to them for the most part, with minimal grinding.
The rear floors however were "patch panels" that were not meant as replacements. It was basically just the footwell, and sized for a Barracuda to boot! I had to return those and explain my situation with having the COMPLETE floor missing there was nothing to patch. I sourced a set of AMD rear floors and now it's all fit up nearly drop in condition. Goodmark makes good patch panels, but for full replacement I'd go AMD.