I've never run anything to cover the filter element other than the rain resistant sock on the street. I never installed the plastic cover for the hood vent that came with my JLT either. I want as much opportunity for air flow as possible. I used to just put the sock on when going through the touchless wash but have gotten in the habit of leaving it on unless I'm at the drag strip and even then I don't know that it matters honestly but makes me feel better to take it off LOL.
OH, and I found a log from my car
bone stock. Starting IAT was 136 and at the top of the quarter 142. That was on 11 pounds of boost and an ambient temp close to 90.
I have tons of logs, if I got real motivated I'd plot them on a graph but honestly not worth the effort. I know what I need to know.
Edited: I also have my intercooler pump speed customized in my tune for best cooling at certain conditions, which helps with temps so that's another variable to consider as well.
Also, look at all the STKR in this log from my car BONE STOCK. No wonder the original motor let loose! I remember that in all my stock logs on 93 and is why I tell everybody never run hard on pump gas.