@BurntMusic and I were talking in another thread about using 0w20 oils in Subaru engines that have approvals under MB 229.71 and VW 508. According to the Lubrizol comparison tool MB 229.71 meets or exceeds VW 508 in all categories other than Aftertreatment Compatibility. MB 229.71 is actually better, per Lubrizol, in the categories of Piston Deposits and Oxidative Thickening. This is convincing me to skip VW 508 oils in favor of a much less expensive MB 229.71 approved Castrol Edge EP 0w20 which is also SP/GF6 approved as well.