A little advance warning
 

Here is a little trick that enables you to know when your car in on the way to the dealership. This applies in the US - don't know about other countries. When the car is actually loaded on the truck to be delivered to the dealer, Mercedes USA automatically adds the car to the dealer's inventory. In addition, they add the car to the on line inventory for the dealer. So if you search the dealer's inventory you will find your car there a couple/few days before it is delivered to the dealership.

My C63 is listed in my dealer's on line inventory even thought it has not been delivered to them yet - maybe today it will actually be delivered.

Correct. That happens when the car is "Wholesaled". It usually takes 10-12 days on average for the car to physically arrive.