My intention was to split the box apart and weld them in as separate pieces. As with any product, I had to trim, fit, trim again and fit some more but that’s the nature of the beast when working on a 48 year old car. After I had the toe board piece fitting the way I wanted, I spray-bombed it for rust protection since the piece does mate face-to-face with the toe board. After I welded it in, I gave the exposed side a shot of paint too. I painted the inside of the second piece to prevent rust and welded it in to the reinforcement panel. Overall, it’s a time consuming job but well worth the effort. I posted a YouTube video of the install. Search for ’65 Mustang Restoration Part 5.5 Torque box installation’. I made a succession of videos in order to cover the entire install. Build quality: The metal used for this piece is thick and very robust. The box is a quality piece for the money if you plan on installing as I outlined above. Very satisfied.