I like it! Curious if wrapping the box with insulation may have an effect on the sound of the unit. Looks like you have a lot of hard flat surfaces in the house. Good job.
I took your advice and put some sound deadening material on the inside of the metal surround. I think it made a noticeable difference, I think before I was getting a lot of kickback noise. I actually thought the exhaust fan wasn't working at first because I couldn't hear it in the room next door.
I also finished the OAK and everything is working great.