Amsoil application guide out of convenience and because other oil companies don't provide the same. See my previous reply. And this is the first time I've mentioned Amsoil since 2009. You're just being malicious. Post some independent test results showing that the VG30DE does not work well with modern 10w-30 since you are challenging. As for your link, fine, I'll take wear protection over fuel-economy any day. "....I'm leaning towards a 5w40 or 10w40 for the southern US," and that's good. I do the same here in the southern U.S. And 40 weight is listed in that Amsoil application guide. REALLY not sure what your argument is with me other than you're just hating. Whatever, it makes no difference to me.