I just put these in when I did a fluid change a couple days ago. I noticed much better contact on these with a hex socket than the oem plugs with the 1/2" ratchet.
Here: http://forums.nasioc.com/forums/showthread.php?t=1884985&highlight=blue+diff+plugs because they are blue.
I put thread tape on them. I am not too worried about getting them out. It was a nightmare getting the stock ones out. I had to use a 4' pipe to get the top one loose and I was scared of rounding it do to the narrow contact area.
You know after soaking them with some Deep Creep I've never had a problem getting them off with a breaker bar. Even the old 91 and 93 T-leg plugs came out fine.
Oh no's! blue aluminum!!! I remember the last time I has blue aluminum nuts on my subi... http://mnsubaru.com/forums/showthread.php?t=35802
^ I am not worried about that issue. These will not need to come out for quite a long time now. at least a year if not 2. Also they are hard aluminum, and if need be I can drill/tap them easily after removing the rear cover on the diff.
That rear diff plate is aluminum too, so you don't have to worry about aluminum plugs seizing in there. And the stock plugs are 13mm, which is why 1/2" doesn't work too well. OEM manual says to use blue loctite when installing the plugs. ~Dan