Couldn't find an easy chart that showed what the "best" would be, but I'd be looking at balsa (isn't that whats used on passenger floor?) or plywood, or maybe just a sheet of acrylic.
Antihero
Putting AMS garbage, and $500 ebay wheels on a Z is like dressing a Victorias Secret model in a Walmart dress and Payless shoes. You're embarrassing yourself.