I was afraid the threads would allow a small vacuum leak. I thought of it though
This is my 3rd x5 but I haven't had the plate off this one yet. It might be in there.
Im afraid to tinker with it on the air pump part if it isn't setting a code. If it runs fine after this and doesn't set any codes I will leave the plug on it and forget about it.
I still need to change the valve cover gasket when that gets here though.