I think that this is a misunderstood engine oil . All I've ever read here was it's a group III Synthetic but it's not group III only these days . Yes it has group III as we know it along with Shells XHVI 5.2 Slack Wax and PAO in the 5w-30 , 10w-30, 10w-40 and the new 5w-40 . The 5w and 10w-30 have been upgraded to A5 recently and I will be interested to see how these oils do in good engines over the previous A1 rating they had . The 5w-50 is formulated differently from what I can tell . I try to find out more about it and the new 5w-20 they have . And that strong detergent smell of the Syntecs , it's Calcium Hypochlorite it appears .