Engine Compartment

I had a local auto / paint store mix up the EV2 I need a put in cans.. What's a firewall foam kit..?
I might be a bit dumb, but I'm almost thinking I'd leave the firewall alone.. It still has the factory assembly line "X's".. Kinda hate to see those go... guess it doesn't really matter...lol
What grit sandpaper you use..?
It was 20 bucks then. The gaskets for the wipers, steering retainer, ect.. 220, then proceed lighter