I've just been reading the specs, they seem very close but there are some slight differences on the specs page, the 15w40 Vantage has extra licence: Renault RN 0700, Renault RN 0710, VW 505 00. They also mention on the semi syn page that they do re label it for Repco stores. Why would they do this just for Repco? Even the extra licencing? Here are the typical data sheets from each.