Here are a few pics of the stuff from Lowes I just installed in my Dart project. Probably not the best but works well for the money. I have used this many times in many old hot rods I have built and like the final results.
Can you post a link to what you used? Does it have adhesive on one side? If not what are you using to get it to stick to the floor? I am looking for a more cost effective material for insulating my duster