In my experience, there's not much difference in quality between panels. Pretty much all of them need to be beat into submission to fit correctly. It's just part of the game.
I believe I've received panels with one vendors PN label pasted over a different vendor's label. Generally speaking, I'd go with the lower priced items. In fact it has been said that they all come out of the same factory in Taiwan.
Jim Carter used to sell that same passenger side floor/toeboard panel, but now sell just the floor section for $85, and a separate full width toeboard. Those two pieces are more correct, assembly wise to the original cabs with a spot weld flange between the floor and toeboard, if that matters.
