My WM always has a lot of QUSUD 5W20 and 5W30 available on the shelf ...My vehicles can use either weight , so with QSUD what specifically am I missing (additives wise ) that should sway me use to M1 or Pennzoil Synthetics (when I can find them in my weight(s) at WM) ? Applications are typical suburban commuter / grocery getter ( '10 Hyundai Elantra PFI engine , '07 Kia Sedona PFI engine)running standard OCI of 6 months / 6500 ~ 7500 miles with Wix filters . No turbo or DI engines to contend with - your thoughts ?