V-spec ... So far I can say from experience (plus a few others), they are one of the best. You can get HKS, Endless etc, but I believe they are rebadged oils anyway. I have seen them at ENOS, I think going for about 200 or so a litre ... and 1 litre would usually be enough, if care is taken to bleed. You don't want to get too much of it, just enough to make one change coz you can never keep this stuff once it's open (I lost almost a litre thru that just letting it sit more than 3 months).
Personally, I have seen it used on Type-R's, Celica GT-4's, etc ... and also some of the works rally team around the world (you can't go wring with that).
Hope it helps, cheers ;)