I also got the passenger side toe board installed awhile ago. It didn’t fit well at all, at least on my car. The bend on the top right edge was completely off, and apparently my side cowl panel or something is off on my car. The panel wouldn’t sit nicely along the edge, so I cut the top part of the toe board and made it a little wider. I could’ve just made a little spacer for the flange where it meets the side cowl, but I thought this might look a little nicer. Anyway, that’s butt welded in and done other than paint and if I feel like fixing any remaining pinholes.
The heater box was removed so that I could have access to put the toe board in. It’s in pretty good shape with just a couple of cracks. I’ll probably replace the heater core before I put it back in.
Random picture of the Mustang: