You might consider "reinforcing" the wheel well liners by some means. The tires sling pebbles into the air, often poking holes in the DACOR liner. Once that happens, every time you tow in rain or on wet roads/through puddles, you force water under the DACOR and onto the "cheap luan surface" of the wheelwell structure.
I bought a 4'x8' sheet of 1/4" HDPE at Menards for $60 and cut it to fit my wheelwells. I just checked the Menards website and it appears their manufacturer is not producing that product and it's no longer available. Possibly other sources are available. Here's the link to what I bought:
https://www.menards.com/main/buildin...4424094192.htm
Previous posts in this thread provide how I installed the HDPE and sealed the edges. Is "my mod" the only means to protect the wheelwells? Certainly not, I'm sure there are many other solutions, this one is just the way I accomplished it.
If you decide to modify your underbelly area, take photos, post your work and any issues you encountered. Other members will gain experience from your work and we all learn from each other.
Good Luck
ADDED: I don't know which keys my fingers were pressing before my first cup of coffee (above) but there's no DACOR underbelly. It's DARCO... Sorry about that if it caused any confusion.....