Dr. T, G-Man and Doyall
It's worth opening the German Castrol site through the babelfish system at
www.altavista.com. Babelfish opens the site translated into English in a window. It all becomes clear after that...
Formula SLX, TWS Motorsport 10w-60 and the others on the
http://www.castrol.de/produkte/a_auto/a_motorenoele/e_werkstatt.html?www.langzeittest.de page are "workshop oils" that are only sold through car makers' dealer networks(like BMW dealers and VW dealers) and not through Castrol retailers like Wal-mart or their euro equivalent.
The lube oil companies and the car companies have realized that they can capture a good market by co-branding products, and Castrol is a leader in this strategy. You, the cautious consumer, can use other oils, but the "recommended by the manufacturer because it will save your warranty" Castrol oil is whats on the dealer's shelf, and that's the only place it is - it's not in retail distribution.
The result is high prices and volumes for both companies and guaranteed sales with no advertising costs. Of course Castrol is bending the rules a bit by relabeling SLX 0w-30 and the corresponding 505.01 oil as Syntec branded oils and selling them in North America, which breaks down the model. But most people don't know the difference, and it cuts the manufacturing costs down by increasing volume.
Neat arrangement. I'm just waiting for it to start with gasoline!
Cheers
JJ