Just a personal thnaks to Terry for taking it up a notch with the Z-oil Study. The state-of-the art formulation info is a bit over my head, but it's good to know that there is serious competition to the oh-so-corporate Mogul 1 from a "blender". Castrol and Audi are corporately linked, and I like that. Audi should just get off their collective asses and start putting this oil into customer cars and forget BC or the 505 version. Here is a product that could have saved Audi MILLIONS on warranty sludge repairs if they used it in their 10k services, but it's really only US BitOGers who appreciate it! Now more than ever, thanks again Terry.