Mobil synthetic is superior to regular oil it runs cooler, it lubricates better,it doesn't break down as fast.The maint schedules are based on using synthetic oil only.Some cars were able to do away with there oil coolers when they went to synthetic mobil one.Most new performance cars come from the factory and specify mobil one corvettes,vipers,srt neons,crossfire.I know mercedes had a problem with there dealers putting in regular oil at service.The customer would follow the maint. schedule for synthetic and ruin there engine.