German Castrol should be fine, same with Mobil 1. I personally used GC and M1 0W40 on my Audi as they are formulated for the German manufacturers and have gotten very excellent oil analysis reviews.
Castrol Product Sheet:
http://www.castrol.com/liveassets/bp...syntec_usa.pdf
Mobil 1 Product Sheet
http://www.mobiloil.com/USA-English/...ge_10W-40.aspx