Go with synthetic,I just had my first oil change,called my local Nissan dealer and they wanted $170
,I went to walmart bought a gallon of Mobil 1 synthetic for $25 and went to my local Honda dealer where a good friend of mine is a mechanic,paid him $30 including filter,moral of the story is go with synthetic,buy your own oil and filter,take it to a reputable shop where you will get a proper reciept and documentation if you are worried about warranty issues