I use marine plywood 3/4 and garage style carpet. Holds up well since 07. I've cut away carpet under machine area.
Did the last van the same in 2000 lasted fine till 2007.
Debating on spray liner for the next, including up the wall a bit, and rocker panels of exterior.
Was only asking because it looked like a nice finish at the side door..
I'm very happy with Raptor liner, some areas have been gouged off due to the sharp edge of a TM hitting it during install, but it took metal with it too, so I don't think ANY bed liner would have held up.