I expect that your wife has been accustomed to driving an American vehicle of some sort with some plush seats. Many years ago, Mercedes research determined that firm seats are MUCH less fatiguing on any trip beyond a short hop for a loaf of bread or a half gallon of milk.

MB's design goals are not to build the most comfortable car in the world. Rather their goals are to build a car that provides safe and controllable driving on the Autobahn at 110 or 120 MPH or more.

Having a seat that feels like your favorite recliner where you keep the remote control is TOTALLY the opposite of what MB is trying to do. This is why they were probably the last mfg in the world to include cup holders. In their thinking a car is not to drink coffee in or to lay back and take a nap in. The German driver is taught that driving is all business. It is even against the law in Germany to have a child less than 10 years old in the front seat.

There are many different types of pads and cushions on the market for those who feel that they have to be comfortable enough to take a snooze while driving.

As someone who spent a number of years covering a four state territory I can testify that I never found a car other than an MB that I could get in and drive 6 hours or more, get out and be ready for my meeting with no fatigue. There's no car that I've ever driven that does it better.

Good luck,