5W40 or 10W40 in 3B engine?

[200q20v]

Fellow listers,

I have been using 10W40 http://www.amsoil.com/storefront/amo.aspx since I bought my car in 03 (280k + miles now). When I got the 12 quart case last year I noticed that the label has changed (UPC code has not) and there is no "Volkswagen 502.00, 505.00, 505.01" listed on the bottle. I still used the case for all my cars but this year I decided to do some more research and found that "Volkswagen 502.00, 505.00, 505.01" is listed only on 5W40 http://www.amsoil.com/storefront/afl.aspx oil.
Please suggest which one is better for year round usage including one or two high speed events.