Don't know much how to test that but in my manual book.. They do recommend to use either mobil 1 15w-50 or 0w-40. This oil is new come out by Mobil " Mobil 1 Extended performance has grade for 15w-50 " .
the only I can tell you that is when I driving the car I can feel it is accerlerate faster with less noise. Also, when I get my foot off the panel, the accerlerate still there some how ..it is not lost power right away. The only thing i am thinking right now if just because the oil will stay inside engine longer (15000 instead 10000) so if I can change engine oil filter twice on the time interval..Would it help to keep the oil sensor and the oil clean and use longer (15000 instead of 10000 which MB recommend)