Some people believe stepping up to a 0w40 or 5W40 Euro A3/B4 Synthetic oil is doing them good in a Hyundai , Kia , etc. GDI engine versus the 5W30 (SP , G-6 , D1G3) rated oil shown in the owner's manual . *The concern I would have - even with M1 0W40FS (closest rating to a 5W30) is the ash content that exceeds 1% (potential cause for IVD) using low SAP USA gasolines . To me , a HTHS of 3.2 ~ 3.5 would be more in line to what I would be looking for in a 5W30 meeting say SP , GF-6 or D1G3 approvals with less than 1% ash ... Any suggestions ?