I agree, the dealer battery is a definite plus on resale. A no-name battery is a real turn off for buyers. I have had nothing but trouble over the years with batteries bought at service stations, Sears, etc. Sure they generally get replaced on warranty but they still leave you stranded on a cold day, or after a few weeks parked. The Mercedes needs a lot of reserve capacity to power its many gadgets and you need to get the top of the line battery to insure that. A top of the line Sears is probably more expensive than the dealer item which has never failed me. Plus there is the radio code issue - Road Service takes care of that!