This is a terrific list.
Keep it up.
By the way Tesla T1 is open-air, and I agree on your IEM comment since the word "IEM" refers to customs most of the time outside of the internet.
I think the extra column adds some clutter and now I feel like there should be three lists, one for UIEM, one for CIEM and one for Headphone...
Thanks for the feedback. I'll probably end up doing something like your last suggestion, and I'll definitely modify the T1 listing.