Box replacing tips

Hey all
So I have a Parts taco laying around with a prime box that happens to have a nice new coat of linex on it. There is also no rust and minimal dents... so naturally I will be swapping it out for my current box. (If you need a new box in the southern Ontario area I will be selling the old one).
During the swap I plan on sanding out some rust and repainting the frame where I can. I also plan on doing the rear diff breather mod.
I am also looking into spraying some high heat insolation underneath the box near the muffler to try and quite down the ride inside the cabin.
Is there anything else I should look into doing while I have the box pulled off? Let me know what you fellas think.
Thanks