I suspect the "don't use synthetic mantra" at the dealership is because they know it uses 0W20, and no one else makes a NON-synthetic version (not that I know of, anyway). By brainwashing you to believe that somehow synthetic is not good for this car (tell me how, someone), then they have captured your oil change dollars. They LOVE simple repetitive services like oil changes. It is a quick profit for the service dept, and they may find (or possibly fabricate) other things you may need while your car is captured in THEIR service bay.

Steve

STOP terrorism - Drive a HYBRID

Vehicles:
350 miles a week ------------ 2006 HCH II, Magnetic Pearl, w/NAVI (born on May 25, 2006)
350 miles a month ---------- 2003 Mazda Tribute ES-V6
350 miles a year (for now) - 1986 Mercedes 560SL