I will be taking my hard-starting E420 to Hartmann Motors in Portland, OR next week. In discussing my problem, Pat Hartmann suggested (in addition to installing a pressure gauge on the fuel rail) looking at the alarm system for electrical faults. When describing my hard-starting occurrences, Pat asked my if after unsuccessful attempts, did I remove my key and reinsert it to attempt another start. I said, "excuse me?" Then he described situations that relate to faults in the ignition system (caused presumably by wear), where the proper signals do not reach the alarm system, essentially preventing the ignition system from energizing. This is way beyond me, so I'm going to bite on having the Merc scoped. Apparently they have a scope similar to those one sees at larger dealerships. Anyway, Im preparing to get financially hosed as this E420 is my wife's daily driver. I'll give more feedback if it seems relatable to E420 starting problems posted by others.