FYI - Over the past few years I have bought two 850s where the oil drain plugs were in so tightly I could not easily remove them even with a 1/2 rachet that had an 18 inch arm. I was fearful of tearing the aluminum threads out of the pan. In both cases I tried an impact wrench and they were easily removed without damage. It is a mystery why some peoply think over torquing spark plugs and oil drain plugs is a good thing.

That's why it's best to do it yourself if you can. All those guys in the oil change joints used impact wrenches to save time. In 45 years driving I've never had anyone else change my oil. Just concider it sort of exercise.