...or should I just have the dealer overcharge me for doing it? : ) The car just went in for an oil change at 15K and they were telling me it's recommended I have it done. I'm somewhat curious, given todays inferior gasolines. I can argue all day about the ethanol additives, but I'm not really interested in that tired debate, but I'm reluctant to spend the extra $2 per gallon for the non ethanol stuff. Anyway, thoughts or scientific debate for or against are welcome. For that matter are fuel additives , like octane boosters OK? I had a Triton V10 in a motor home a couple years ago and that thing would knock like crazy on regular pump gas, 2 bottles of octane booster stopped it. I don't own it any more, but wonder about long term issues using it.