It's probably normal, some cars tend to follow the road crown more than others. If you really think it's an issue, you can have them look at the alignment when you bring it in for an A-service. Don't just ask for the alignment bolts out of the blue, or you will be charged for them. The bolts may be needed later on, but it's not something you need right away. It's something like getting braces for your kid as soon as they start to develop teeth. Unless the alignment is truly out of whack, then the bolts are free. It's a little tough to explain, but it's like this: if the alignment is okay, and you ask for the bolts to be installed, this will result in you definitely needing an alignment. Since the car was fine when it came in for service, and something you request will put the car out of specs, you will be charged to correct it. If the car really IS out of alignment, then it's Mercedes' fault and the alignment and bolts will be covered under warranty. The reason they aren't put in at the factory is this: the cars are designed and engineered to go straight, and they are built at the factory with correct alignment specs. When something like suspension wear, parts replacement, or road hazards put the suspension out of alignment, THEN the bolts are needed to correct it. This is the same reason new cars don't come with starter shims, brake pad shims, etc. They were designed to be right the first time, and if something happens down the road, then you might need extra shims.