Walmart sells exercise mats for treadmills etc. for 20 bucks. I used one for the rear floor and made patterns with cardboard and then cut front ones from the mat roll. They are pretty soft. I then just bought universal black mats from Walmart's floor mat section and fit them over the top of the soft mats in front. You have to shop to find mats that don't have football spike bottoms!!!!!!!!!!!! I hate those. They were made to grip carpet, not paint.
If you want sound deadener, ebay sells closed cell black foam you can cut into needed shapes also.
John