I like that little snap-in window you have between the seats. I drove a Chevy Express one summer, and it had a metal door there that rattled all the time.
Probably helps keep the driver's compartment heated/cooled to a comfortable temperature, too, since it's not perforated.
It was pouring rain today so I ran some air lines in my friends steel building.
Those LED lights , I put up when he built the building last year. I'm liking the light they put out.