...and I'm thinking that I don't have padded insulation in the engine bay, but do on the interior.
There is a firewall (sort of...a hard plastic wall) that fits in front of the left rear part of engine bay...on intake side...through which the hose from upper intake boot passes before brake booster...don't think that's the missing part you have in photo though.
Let's see how realoem treats me...brb!
Upcoming NYC dates: Jan 8 and 27. See Facebook for other shows and PM me if you can make one...love to see you there!
Mangofy your E46!