I always attribited the lazy engine when cold was just the thick oil. Until it warms and gets flowing a little easier the internal drag seems very high. You could perhaps lessen the symptom by going to a synthetic oil or perhaps semi synthetic oil. Better overall milage as well I understand. Might even make up for the higher initial cost. My 240ds exibit the same tendency but even worst but both are on regular oil as well. Perhaps the only cars I own that I let warm up before counting on much of any performance at all. Never would contemplate for example just starting one cold and entering a freeway for example or I would expect to be on shoulder letting engine warm a little before being able to go fast. With engine stone cold and facing a hill I would consider the word doggy to be an understatement. The five cylinder non turbos are perhaps a little better but not much in my opinion. You sort of get conditioned to it.