I've had three of them,(in different benz's) and I would rate their battery's as pretty reliable, at least for a diesel benz. The model they make for the benz diesels have a 900+ CCA, which helps out in the winter...

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240_Dizzell

74 240D Auto,Beige (Totaled)
82 240D 4-Speed Manual,Gray (Retired) 260,000
97 E300 D Auto, Blue (Current) 240,000
05 E320 CDI Auto,TITANITE RED (Current) 158,000