Actually, bedliner works very well under wheel wells. I have a friend that installs it, and I was curious about just that, so I called him and asked about it. Seems quite a few people are doing it. It does not need to be as thick as when sprayed as a bedliner. He says it is best to do the fenders off the truck, but that gives a problem of covering the bolt holes, so you will ask your guy how he will solve that problem.
