Thanks for posting this up. Did you do an oil analysis on the BMW Synthetic? I'd be interested to see how it holds up.
I plan to switch to Castrol EDGE 5W-30 after my next change, and will also do the oil analysis, but that's a long time away
I already have Castrol EDGE 5W-30 in our 2 other turbo cars, a VW Beetle 1.8T, and an Audi TT Quattro. I'll be performing a used oil analysis on those cars at the 10K mark. For those who don't know, Castrol EDGE just became available in the states in 2009. It's a great oil formerly available only in Europe.
Reason I'm doing it at the 10K mark is because I've been changing my oil at the 7.5K mark. I asked myself one day, 'why 7.5K, and why does everyone say 7.5K?' It seems like 7.5K is repeated so often, it somehow became THE STANDARD (like 5K was for previous cars using Mobil 1). But no matter how much I searched for used oil analysis reports, I couldn't get any data. In comparison, there were a lot of used oil analysis for 5K synthetic oil changes on older generation cars....which is different from our car, because of our 15K oil change interval.
Thanks Craig for putting this up.